ESG assurance is not simply a final check on a sustainability report. The process can affect how confidently an organisation presents its environmental, social, and governance data to investors, regulators, customers, and other stakeholders.
The UK has a broad mix of ESG assurance providers, including international professional services networks, accountancy firms, sustainability consultancies, and specialist verification bodies. Their work may cover greenhouse gas emissions, climate disclosures, sustainability metrics, reporting controls, and alignment with recognised assurance standards.
This guide looks at a selection of companies providing ESG assurance services in the UK. It is not a ranking. The aim is to give practical context on who these firms are, the organisations they work with, and the ESG reporting and assurance matters they typically handle.
Acumon
Acumon is a UK firm of chartered accountants and registered auditors providing ESG assurance services to companies, charities, regulated organisations, and international corporate groups.
The firm works with organisations ranging from growing owner-managed businesses and charities to larger corporate groups and regulated entities. ESG assurance engagements focus on the reliability of environmental, social, and governance information, supported by a structured risk-based methodology and an assessment of the processes, evidence, and controls behind reported data.
Acumon holds a Public Interest Entity (PIE) audit licence, allowing the firm to work with listed companies and other entities subject to enhanced regulatory oversight in the United Kingdom. This experience is valuable for ESG assurance engagements where boards, investors, regulators, and other stakeholders expect clear reporting, strong governance, and independently reviewed information.
Alongside its UK audit registration, Acumon holds audit licences in several international financial centres, including the Cayman Islands, British Virgin Islands (BVI), Jersey, and Isle of Man. These registrations support the firm’s work with international corporate groups whose reporting structures extend across several jurisdictions.
International group structures frequently combine UK operating companies with offshore holding entities, particularly in sectors such as investment management, technology, energy, and international trade. ESG reporting across these structures requires consistent definitions, reliable data collection, clear reporting boundaries, and coordination between entities responsible for sustainability information.
Acumon works with finance teams, boards, and senior management to support ESG reporting and assurance requirements while strengthening the governance arrangements, internal controls, documentation, and reporting processes behind environmental, social, and governance disclosures.
ESG Assurance Capabilities:
Acumon provides ESG assurance services across a wide range of organisational structures and sectors.
These include:
- UK limited companies and corporate groups
- Public Interest Entities (PIEs) and regulated organisations
- UK subsidiaries of international groups
- charities and not-for-profit organisations
- owner-managed businesses developing formal ESG reporting processes
- offshore holding companies and investment vehicles
ESG assurance engagements are led by senior professionals who remain directly involved throughout the work.
Regulatory Licences and Registrations:
Acumon holds several audit registrations that support assurance work for organisations operating across multiple jurisdictions.
These include:
- UK statutory audit registration
- Public Interest Entity (PIE) audit licence
- Jersey audit licence
- Isle of Man audit licence
- Cayman Islands audit licence
- British Virgin Islands audit licence
These registrations allow the firm to work with groups containing entities in the UK and key international financial centres, where ESG information needs to be reviewed across different reporting environments and corporate structures.
Core Services:
Alongside ESG assurance, Acumon provides services that support sustainability reporting, risk management, financial oversight, and governance.
These include:
- independent ESG reporting assurance
- review of environmental, social, and governance data
- assessment of ESG reporting controls and processes
- sustainability reporting readiness reviews
- governance and internal control reviews
- risk management and compliance support
- assurance over information collected across international group structures
ESG assurance work is delivered alongside discussions with management and boards regarding reporting responsibilities, data ownership, governance frameworks, control processes, and the evidence supporting published disclosures.
Many organisations begin formalising ESG reporting as stakeholder expectations increase, reporting frameworks develop, and environmental and social information becomes more closely connected with corporate reporting.
Acumon works with businesses that are:
- preparing their first formal ESG or sustainability report
- responding to investor or stakeholder reporting expectations
- developing ESG data collection and control processes
- expanding into international markets
- operating within corporate group structures
Early engagement with an assurance firm supports the development of reporting systems, documentation, governance procedures, and internal controls that align with the organisation’s ESG reporting objectives.
Contact Information:
- Website: acumon.com
- Phone: 020 8567 3451
- E-mail: mail@acumon.com
- Address: 1-2 Craven Road, Ealing, London, W5 2UA, UK
Price Bailey
Price Bailey is a UK firm of chartered accountants and business advisers. They work with individuals, companies, charities, public sector organisations, and businesses across sectors such as financial services, technology, healthcare, manufacturing, property, education, and utilities.
Their wider practice covers audit and assurance, accounting, tax, corporate finance, business structuring, employment law, and strategic advice. ESG assurance sits within their audit and assurance work, alongside specialist support from teams dealing with financial reporting, governance, risk, and sector-specific requirements.
Key Highlights:
- UK chartered accountancy and business advisory firm
- Partner and manager-led working structure
- Offices across the UK and selected international locations
- Sector teams covering private, public, and not-for-profit organisations
- ESG assurance within the wider audit and assurance practice
Services:
- ESG assurance
- Audit and assurance
- Accounting and outsourcing
- Tax consultancy
- Corporate finance
- Group structuring
- Employment law and HR
- Strategic planning
Contact Information:
- Website: www.pricebailey.co.uk
- Phone: 020 7065 2660
- E-mail: city@pricebailey.co.uk
- Address: 8th Floor, Dashwood House, 69 Old Broad Street, London EC2M 1QS
- Facebook: www.facebook.com/PriceBaileyLLP
- Twitter: x.com/price_bailey
- LinkedIn: www.linkedin.com/company/price-bailey
- Instagram: www.instagram.com/pbpeople
Aureliant Global Advisory
Aureliant Global Accountants is a UK-registered firm of chartered accountants and advisers operating from London. They work across accounting, finance, tax, internal audit, governance, regulatory reporting, ESG, digital transformation, and cross-border advisory.
Their delivery model uses structured methodologies, evidence-based analysis, senior involvement, and clear reporting throughout an engagement. ESG work covers strategy, disclosures, sustainability governance, energy transition, and the integration of environmental and social considerations into reporting and business oversight. Their audit and assurance activity is described as advisory support that respects applicable independence requirements.
Key Highlights:
- UK-registered chartered accountancy and advisory firm
- London-based delivery with international coordination
- Partner-led engagement model
- ESG integrated into reporting, governance, and strategy
- Structured and evidence-based working methods
- Cross-border work across several regions
Services:
- ESG and sustainability advisory
- ESG reporting and disclosures
- Sustainability governance
- Audit and assurance advisory
- Accounting advisory
- Internal audit
- Regulatory reporting and compliance
- Energy transition advisory
- Risk and governance
- Digital, data, and AI advisory
Contact Information:
- Website: aureliant.co.uk
- Phone: +44 (0)20 7967 1177
- E-mail: info@aureliantglobal.com
- Address: 70 St Mary Axe, London, EC3A 8BA
- Facebook: www.facebook.com/aureliant
- Twitter: x.com/aureliant
- LinkedIn: www.linkedin.com/company/aureliant
- Instagram: www.instagram.com/aureliant
Naylor Accountancy Services
Naylor Accountancy Services is a UK accountancy practice working with business owners, partners, and managing directors. They began by supporting local businesses in Kent and later expanded through offices in the UK and Canada.
Their work combines accountancy with business planning, growth support, profit management, and exit strategy planning. They also publish guidance on financial and business matters, including the growing use of ESG assurance by UK companies. The supplied information does not identify a separate ESG assurance engagement service or describe an assurance methodology.
Key Highlights:
- UK accountancy practice
- Works directly with business owners and management teams
- Offices in the UK and Canada
- CIMA registered
- Xero Gold Partner
- Profit First certified
- QuickBooks ProAdvisor
Services:
- Accountancy
- Business planning
- Profit First support
- Growth planning
- Scaling and investment support
- Exit strategy planning
- Financial and business guidance
Contact Information:
- Website: www.nayloraccountancy.com
- Phone: +44 (0)1892 807 001
- E-mail: accounts@nayloraccountancy.com
- Address: 201 Borough High Street, London SE1 1JA
- Facebook: www.facebook.com/NaylorAccountancyServices
- LinkedIn: www.linkedin.com/company/naylor-accountancy
Pioneers Ltd
Pioneers Ltd presents themselves as a UK audit, accounting, tax, and advisory practice operating within an international partnership. They work with private businesses, SMEs, larger corporate groups, start-ups, public organisations, and individuals.
Their service structure brings together audit and assurance, accounting, tax, financial advice, consulting, outsourcing, and sustainability work. ESG is treated as part of a wider sustainability practice, supported by the firm's broader audit and advisory capabilities. The material provided does not set out the standards, procedures, or evidence-testing methods used in ESG assurance engagements.
Key Highlights:
- UK audit, accounting, tax, and advisory practice
- Integrated partnership structure
- Works with private, corporate, and public sector clients
- Sustainability and ESG service line
- Audit and assurance practice
- International operating network
Services:
- ESG assurance services
- Sustainability and ESG
- Audit and assurance
- Accounting
- Tax
- Financial advisory
- Consulting
- Outsourcing
- Privately owned business services
Contact Information:
- Website: pioneersltd.co.uk
- Phone: 02071128997
- E-mail: info@pioneersltd.co.uk
- Address: The Mille, 1000 Great West Road, Brentford, Middlesex, TW8 9DW
Bishop Fleming
Bishop Fleming is a UK accountancy and advisory firm with offices across the South West, West Midlands, and other parts of the country. They work with owner-managed businesses, SMEs, larger organisations, charities, schools, public bodies, entrepreneurs, and private individuals.
Their practice spans external audit, internal audit, risk assurance, accountancy, tax, corporate finance, reporting, and business advisory. ESG work sits within a broader set of services covering responsible business, governance, energy, renewables, natural resources, reporting, and organisational risk. Their teams combine local sector knowledge with international coordination through Kreston Global.
Key Highlights:
- UK accountancy and advisory firm
- Offices across several UK regions
- Works with commercial, public, education, and charity clients
- International connections through Kreston Global
- External and internal audit capabilities
- Sector knowledge in energy, renewables, and natural resources
Services:
- ESG services
- External audit
- Internal audit and risk assurance
- Accountancy
- Business strategy and advisory
- Financial reporting
- Management information services
- Corporate finance
- Tax compliance
- Energy and renewables sector support
Contact Information:
- Website: www.bishopfleming.co.uk
- Phone: 0117 9100250
- Address: 10 Temple Back, Bristol, BS1 6FL
- Facebook: www.facebook.com/people/Life-at-Bishop-Fleming/100093464198343
- Twitter: x.com/BishopFlemingUK
- LinkedIn: www.linkedin.com/company/bishop-fleming-chartered-accountants
- Instagram: www.instagram.com/bishopfleminguk
Grant Thornton UK
Grant Thornton UK provides audit, tax, and advisory services to private businesses, listed organisations, public sector bodies, and other institutions. Their UK practice operates as part of the wider Grant Thornton international network, with services delivered by separate member firms in their respective markets.
Their work combines specialist teams with senior involvement and technology-supported analysis. ESG forms a distinct part of the UK service offering alongside audit and assurance, consulting, financial services advisory, cyber, deals, restructuring, tax, and public sector work. Their stated approach places professional judgement at the centre of engagements, with technology used to handle data-heavy and process-based tasks.
Key Highlights:
- UK audit, tax, and advisory practice
- Part of an international network of separate member firms
- Senior-led client work
- Technology-supported analysis
- Dedicated ESG service area
- Experience across private and public sector organisations
Services:
- ESG services
- Audit and assurance
- Consulting
- Tax
- Financial services advisory
- Cyber advisory
- Deals and transaction support
- Forensics and investigations
- Restructuring
- Government and public sector advisory
Contact Information:
- Website: www.grantthornton.co.uk
- Phone: +44 (0)11 7305 7600
- Address: 2 Glass Wharf, Bristol BS2 0EL
- LinkedIn: www.linkedin.com/company/grant-thornton-uk
- Instagram: www.instagram.com/gt_trainees
KPMG UK
KPMG UK is a professional services firm working across audit, advisory, tax, legal, artificial intelligence, and sustainability. They organise their work around specialist service and industry teams, combining sector knowledge with data, technology, and professional judgement.
Their sustainability practice deals with the commercial, operational, and reporting questions created by the transition to a lower-carbon economy. Alongside this work, their audit teams examine financial reporting and the systems, processes, and evidence behind it, while advisory specialists work on transactions, technology change, innovation, and risk.
Key Highlights:
- UK professional services firm
- Separate audit, advisory, tax, legal, and sustainability practices
- Industry-focused teams
- Technology and data used across engagements
- Research covering energy transition and net zero
Services:
- Audit
- Sustainability
- Advisory
- Risk consulting
- Artificial intelligence advisory
- Tax
- Legal services
- Technology transformation
Contact Information:
- Website: kpmg.com
- Phone: +44 (0)161 246 4000
- Address: 1, St Peter's Square, Manchester M2 3AE, United Kingdom
- Twitter: x.com/kpmguk
- Facebook: www.facebook.com/KPMG
- LinkedIn: www.linkedin.com/company/kpmg-uk
Kreston Reeves
Kreston Reeves is a full-service accountancy firm with offices across London, Kent, and Sussex. They work with organisations at different stages of ESG reporting, from those responding to statutory requirements or customer data requests to businesses developing a wider sustainability programme.
They begin by looking at the organisation's existing position, reporting obligations, available data, and practical priorities. From there, they set out deliverables and timelines, carry out materiality and carbon assessments, and work on reporting processes, climate planning, and data quality. Their wider audit, tax, and business advisory teams are brought into projects where the work crosses into financial reporting or broader business planning.
Key Highlights:
- Dedicated ESG advisory team
- Offices in London, Kent, and Sussex
- Collaborative scoping and assessment process
- ESG data considered alongside financial information
- Technology-led approach to data collection and reporting
- Access to audit, tax, and business advisory specialists
Services:
- ESG scoping assessments
- Impact and financial materiality assessments
- Streamlined Energy and Carbon Reporting
- Carbon footprint calculations
- Climate action plans
- CSRD support
- ESG compliance advice
- Sustainability reporting
- Data and reporting process design
Contact Information:
- Website: www.krestonreeves.com
- Phone: +44 (0)330 124 1399
- Address: 2nd Floor, 168 Shoreditch High Street, London, E1 6RA
- Twitter: x.com/KrestonReeves
- LinkedIn: www.linkedin.com/company/kreston-reeves
Menzies
Menzies is an independent UK accountancy and business advisory practice working with privately held companies, larger corporate groups, not-for-profit organisations, and individuals. Their teams are organised across audit, tax, assurance, and advisory disciplines, with sector specialists involved where an engagement requires detailed industry knowledge.
They take a relationship-led approach, keeping financial, operational, and strategic questions within the same conversation rather than treating them as separate pieces of work. ESG assurance forms part of their strategic business advisory offering, supported by their broader experience in audit, governance, reporting, risk, and compliance. International work is coordinated through the HLB accounting and advisory network.
Key Highlights:
- Independent UK accountancy and advisory practice
- National coverage across England and Wales
- Relationship-led working model
- Sector-focused teams
- Certified B Corp
- International coordination through HLB
Services:
- ESG assurance
- Audit and assurance
- Strategic business advisory
- Accounts
- Tax services
- Deal advisory
- Forensic accounting
- Restructuring and insolvency
- Outsourced business services
- Valuations
Contact Information:
- Website: www.menzies.co.uk
- Phone: +44 (0)333 091 0411
- Address: The Colmore Building, 20 Colmore Circus Queensway, Birmingham B4 6AT
- LinkedIn: www.linkedin.com/company/menzies-llp
- Instagram: www.instagram.com/menzies_llp
Moore Kingston Smith
Moore Kingston Smith is a multidisciplinary audit, tax, and advisory firm working with businesses, charities, membership bodies, investors, and organisations across a broad mix of sectors. They combine local delivery with international coordination through the Moore Global network.
Their sustainability and ESG practice sits alongside audit, risk advisory, outsourced accounting, digital transformation, and third-party assurance. This structure allows their teams to address ESG reporting as part of the organisation's wider systems, controls, governance, and business planning rather than treating sustainability information in isolation.
Key Highlights:
- UK audit, tax, and advisory firm
- Multidisciplinary service structure
- Member of the Moore Global network
- Sustainability and ESG practice
- Separate risk and third-party assurance services
- Experience across commercial and nonprofit sectors
Services:
- Sustainability and ESG services
- Audit
- Third-party assurance
- Risk advisory
- Business growth advisory
- Digital transformation
- Outsourced accounting
- Corporate finance
- Tax
- Nonprofit advisory
Contact Information:
- Website: mooreks.co.uk
- Phone: +44 (0)20 4582 1000
- Address: 6th Floor, 9 Appold Street, London, EC2A 2AP
- Twitter: x.com/MooreKSLLP
- LinkedIn: www.linkedin.com/company/moore-kingston-smith
Saffery
Saffery is a UK accountancy and advisory firm with a specialist sustainability team. They work with privately owned businesses, family enterprises, mid-market companies, and international groups on the systems, reporting, and governance behind environmental, social, and governance information.
Their process often starts with a maturity or materiality assessment. The team examines current practices, identifies the issues that matter most to the organisation and its stakeholders, and produces a structured basis for reporting and future work. They also advise on recognised reporting frameworks, provide assurance over ESG disclosures, and work on carbon accounting, due diligence, and natural capital.
Key Highlights:
- Specialist sustainability team
- Work with privately owned and mid-market organisations
- Evidence-led assessment process
- Single and double materiality approaches
- Work aligned with ISSB and ESRS frameworks
- Sustainability reporting linked to established accounting disciplines
Services:
- ESG assurance over disclosures
- Sustainability maturity assessments
- ESG materiality assessments
- Sustainability reporting support
- ESG due diligence
- Carbon accounting system implementation
- Natural capital recognition
- Regulatory framework advice
- Governance and policy development
Contact Information:
- Website: www.saffery.com
- Phone: +44 (0)20 7841 4000
- E-mail: info@saffery.com
- Address: 71 Queen Victoria Street, London EC4V 4BE, UK
- LinkedIn: www.linkedin.com/company/saffery
- Instagram: www.instagram.com/saffery_uk
BDO UK
BDO UK is an accountancy and business advisory firm providing audit, tax, deals, consulting, risk, and outsourcing services. They work mainly with entrepreneurial, growing, and mid-market organisations, while drawing on specialists from the wider BDO international network for cross-border matters.
Their sustainability and ESG work covers both client services and the firm's own governance and environmental commitments. ESG readiness and assurance sit within a broader advisory structure that also deals with reporting, risk, controls, business operations, and regulatory expectations. Their stated approach to technology and AI keeps human accountability, transparency, security, and ethical use at the centre of delivery.
Key Highlights:
- UK accountancy and business advisory firm
- Focus on entrepreneurial and mid-market organisations
- ESG readiness and assurance service
- International network access
- Audit, risk, and consulting teams within the same practice
- Formal principles for responsible use of AI
Services:
- ESG readiness
- ESG assurance
- Sustainability advisory
- Audit
- Tax
- Deals
- Consulting
- Risk advisory
- Outsourcing
- Reporting and governance support
Contact Information:
- Website: www.bdo.co.uk
- Phone: 0161 817 7500
- Address: Eden Building, Irwell Street, Salford, Manchester, M3 5EN, United Kingdom
- LinkedIn: www.linkedin.com/company/bdo-llp
- Instagram: www.instagram.com/bdo_uk
Forvis Mazars UK
Forvis Mazars UK is an audit, tax, and advisory firm operating through offices across the country. They are part of a global professional services network made up of Forvis Mazars in the United States and the internationally integrated Forvis Mazars partnership.
Their teams work across accounting, assurance, consulting, financial advice, tax, outsourcing, and sustainability. Engagements are organised around the client's industry and operating environment, with specialist knowledge drawn from areas including financial services, energy, infrastructure, technology, manufacturing, private equity, and the public sector.
Key Highlights:
- UK audit, tax, and advisory firm
- Part of the Forvis Mazars global network
- Industry-based specialist teams
- Integrated international partnership structure
- Dedicated sustainability service area
- Work across private, public, and regulated sectors
Services:
- Sustainability
- Audit and assurance
- Accounting and outsourcing
- Consulting
- Financial advisory
- International business services
- Tax
- Private client services
Contact Information:
- Website: www.forvismazars.com
- Phone: +44(0) 161 238 9200
- Address: One St Peters Square, Manchester, M2 3DE, United Kingdom
- Twitter: x.com/ForvisMazarsUK
- LinkedIn: www.linkedin.com/company/forvis-mazars-in-the-uk
- Instagram: www.instagram.com/forvismazarsuk
Conclusion
Choosing an ESG assurance provider usually starts with the organisation's reporting position. Some businesses need assurance over a specific set of disclosures, while others are still working through data quality, reporting controls, materiality, or the requirements of a particular framework. The right provider should understand that starting point, explain the scope clearly, and set out what evidence, systems, and internal involvement the work will require.
Sector experience, assurance methodology, independence, and knowledge of the relevant reporting standards all matter. Organisations should also look at how the provider works in practice - who leads the engagement, how findings are communicated, and whether the team has the technical depth to deal with carbon data, governance, supply chains, or wider ESG metrics.
This guide brings those differences into one place. It gives organisations a clearer view of the types of ESG assurance services available in the UK and the wider expertise each firm brings. It is not a ranking, but a practical starting point for narrowing the field and deciding which providers are worth speaking to in more detail.