1. PricewaterhouseCoopers LLP (PwC)
Description: One of the “Big Four” global professional services networks, offering audit, tax, consulting and advisory services worldwide. (London Business Mag)
Address: 7 More London Riverside, London SE1 2RT. (The Big 4 Accounting Firms)
Postcode: SE1 2RT
Comment: With its seat in London and extensive services, PwC remains a first‐port of call for large corporates, financial institutions and major transactions.
2. Deloitte LLP
Description: Global professional services network (audit, tax, consulting, risk). One of the largest in the “Big Four”. (Cox Hinkins)
Address: 1 New Street Square, London EC4A 3HQ. (IBM)
Postcode: EC4A 3HQ
Comment: Known for its cross-discipline advisory and large scale engagements, especially in digital transformation and risk.
3. Ernst & Young LLP (EY)
Description: Another of the Big Four, EY offers assurance, tax, transactions, consulting and strategy services. (Cox Hinkins)
Address: 1 More London Place, London SE1 2AF. (Charity Register)
Postcode: SE1 2AF
Comment: EY focuses significantly on innovation, advisory services and works with large international clients and complex deals.
4. KPMG LLP
Description: The fourth of the Big Four, KPMG provides audit, tax and advisory services globally. (Wikipedia)
Address: 15 Canada Square, London E14 5GL. (Wikipedia)
Postcode: E14 5GL
Comment: Strong in audit and advisory work, especially in sectors like financial services and infrastructure.
5. Grant Thornton UK LLP
Description: Major professional services firm, strong in audit, tax and advisory for mid-market businesses and public sector. (SKZ Chartered Certified Accountants)
Address: 8 Finsbury Circus, London EC2M 7EA. (Grant Thornton International Ltd. Home)
Postcode: EC2M 7EA
Comment: Good choice for companies outside the largest “Big Four” bracket; strong mid-market presence.
6. BDO UK LLP
Description: Large UK accounting and advisory firm, serving mid-market and entrepreneurial businesses. (huzzle.com)
Address: 55 Baker Street, London W1U 7EU. (BDO UK)
Postcode: W1U 7EU
Comment: Offers full-service capabilities with a more flexible and entrepreneurial ethos compared to the very largest players.
7. Mazars UK
Description: International audit, accounting, tax and advisory firm; well known in the UK market for breadth of services. (Listed among top UK firms) (fnlondon.com)
Address: 1 City Place House, 55 Basinghall Street, London EC2V 5DU. (Common London office address.)
Postcode: EC2V 5DU
Comment: Strong reputation for agility and international network support, often slightly more accessible than the Big Four.
8. Moore UK (formerly Moore Kingston Smith)
Description: UK member of the Moore Global network; delivers audit, tax, advisory and consulting services, especially to SMEs and growth businesses. (SKZ Chartered Certified Accountants)
Address: 9 Aldermanbury, London EC2V 7AE.
Postcode: EC2V 7AE
Comment: A good alternative for growing businesses seeking a partner that combines size and entrepreneurial mindset.
9. UHY Hacker Young Group
Description: UK and international chartered accounting group established 1925 in London. Strong in tax, advisory, business services and international operations. (Wikipedia)
Address: 15 Finsbury Square, London EC2A 1NY.
Postcode: EC2A 1NY
Comment: Particularly useful for internationally-oriented businesses and those needing bespoke advisory services.
10. Baker Tilly International Ltd (UK network)
Description: Global network of independent accounting and advisory firms. UK entity based in London; offers audit, tax, advisory, business services. (Wikipedia)
Address: 2 London Wall Place, London EC2Y 5AU. (Wikipedia)
Postcode: EC2Y 5AU
Comment: Strong network for international reach and mid-market clients with cross-border needs.
Here are profiles, full addresses (including postcodes), case studies, and commentary for the top 10 accounting / professional services firms in London. This selection focuses on firms with a strong London presence, including both the “Big Four” and leading mid-tier players.
1. PricewaterhouseCoopers LLP (PwC)
Address: 7 More London Riverside, London SE1 2RT. (PwC)
Description: A global “Big Four” professional services firm offering audit, assurance, tax, advisory and consulting services. (vintti.com)
Case Study: PwC developed “Halo,” a data-audit tool, winning “Audit Innovation of the Year” in London for its use of big data and analytics to reshape assurance. (Finance Americas) It also achieved BREEAM “Outstanding” rating for its More London Riverside office, demonstrating a commitment to sustainability in its UK HQ. (PwC)
Commentary: PwC’s case shows how heritage audit brands are being reinvented via technology and ESG credentials. Their size and brand prestige make them a go-to for very large corporates, but the regulatory scrutiny (see audit-quality challenges) means clients need to monitor risk.
2. Deloitte LLP
Address: 1 New Street Square, London EC4A 3HQ. (This is a principal London address for Deloitte’s UK operations.)
Description: Another of the Big Four, Deloitte delivers audit, tax, consulting, risk advisory, and increasingly digital transformation services. (Business Insider)
Case Study: Deloitte launched a service called Propel by Deloitte for start-ups and SMEs: a cloud-based accounting/analytics platform combining bookkeeping and KPI dashboards. (cambridgenetwork.co.uk) In London they also expanded their office footprint post-pandemic by taking on ~70,000 ft² near New Street Square to support evolving ways of working. (Financial Times)
Commentary: Deloitte’s case demonstrates how even large audit firms must diversify into tech-enabled services and adjust real estate strategy. Their focus on SMEs (via Propel) broadens their market beyond just large corporates.
3. Ernst & Young LLP (EY)
Address: 1 More London Place, London SE1 2AF. (Charity Register)
Description: Yet another Big Four firm, EY offers assurance, tax, advisory, transactions and consulting services globally. (vintti.com)
Case Study: EY relocated its UK Global Headquarters to a new “Workplace of the Future” at 6 More London Place, reflecting emphasis on collaborative hubs and technology-enabled workspaces. (consultancy.uk)
Commentary: EY’s transformation around workspace and technology indicates how audit firms are rethinking their core infrastructure. However, recent regulatory issues (e.g., audit fines) show that prestige alone isn’t enough — quality and compliance are critical. (accountingweb.co.uk)
4. KPMG LLP
Address: 15 Canada Square, London E14 5GL.
Description: The fourth Big Four firm, KPMG is strong in audit, tax and advisory services with significant focus on financial services and infrastructure. (vintti.com)
Case Study: KPMG (together with PwC) was recognised for audit innovation in London, and has invested heavily in data-analytics for audit (e.g., using “smart audit” tools) to gain awards. (Finance Americas)
Commentary: KPMG’s case underlines the intensifying competition among audit firms for tech-led audit services. For clients, this means potential benefit from improved analytics — but also the importance of choosing firms with proven audit-quality track record.
5. Grant Thornton UK LLP
Address: 8 Finsbury Circus, London EC2M 7EA.
Description: A leading mid-tier accounting & advisory firm in the UK, strong in audit, tax and business advisory for mid-market enterprises. (Vertix Auditing)
Case Study: Grant Thornton has leveraged its mid-market positioning by offering agile advisory services (including M&A, restructuring) and focusing on growth companies often overlooked by Big Four.
Commentary: For companies at mid-market level, Grant Thornton offers strong capabilities, perhaps with more flexibility than the biggest global firms. Their case illustrates the value of specialization and responsiveness.
6. BDO UK LLP
Address: 55 Baker Street, London W1U 7EU. (London Business Mag)
Description: A major UK accounting and advisory firm serving entrepreneurial businesses and larger SMEs, offering audit, tax, and consultancy. (Vertix Auditing)
Case Study: BDO has positioned itself as a trusted partner for growing companies, combining global reach with mid-market agility — enabling them to capture clients who may find Big Four too large or inflexible.
Commentary: BDO’s model shows how a mid-tier firm can compete by offering a combination of global network and client-focused service. For business owners seeking attentive service, this may be attractive.
7. Mazars UK
Address: 1 City Place House, 55 Basinghall Street, London EC2V 5DU.
Description: International audit, accounting, tax and advisory firm present in the UK, known for agility and international network support. (Vertix Auditing)
Case Study: Mazars has grown via international network strategy and has emphasised independence and audit quality — making itself an alternative to the Big Four for audits with global complexity.
Commentary: The Mazars case highlights how newer generation firms can carve out a niche by emphasising transparency, international coverage and service quality rather than sheer size.
8. Moore UK (formerly Moore Kingston Smith)
Address: 9 Aldermanbury, London EC2V 7AE.
Description: Part of the Moore Global network, offering audit, tax, advisory and consulting services, especially to SMEs and growth-oriented businesses. (Wikipedia)
Case Study: Moore UK has focused on growth-business segments, combining traditional accounting services with consulting for the entrepreneurial sector, enabling them to capture clients earlier in growth cycles.
Commentary: For firms that are scaling (rather than large multi-nationals), Moore UK provides a fitting alternative: less “corporate” than Big Four, but with credible expertise and network.
9. UHY Hacker Young
Address: 15 Finsbury Square, London EC2A 1NY.
Description: A UK chartered accounting group established in London in 1925, offering accounting, audit, tax, advisory, international business services. (Wikipedia)
Case Study: UHY has leveraged its longevity and London base to support international businesses, especially ones expanding into/out of the UK, by using its network of 100+ countries.
Commentary: UHY’s case emphasises how networked mid-tier firms can serve internationally-oriented clients with tailored service — useful for clients beyond the largest corporates.
10. Baker Tilly International Ltd (UK)
Address: 2 London Wall Place, London EC2Y 5AU. (Wikipedia)
Description: Global network of independent accounting and advisory firms; the UK entity based in London offers audit, tax, advisory and business services with international reach. (Wikipedia)
Case Study: Baker Tilly in the UK has grown via combining accounting services with legal, real-estate advisory and risk management services — creating a diversified professional-services model. (SKZ Chartered Certified Accountants)
Commentary: Baker Tilly shows how an accounting firm can evolve into a broader advisory firm — clients looking for more than audit/tax (e.g., real-estate, legal) may find this model compelling.
🧭 Key Themes & Comments
- Scale vs. agility: The Big Four (PwC, Deloitte, EY, KPMG) deliver immense scale and global reach, but mid-tier firms (Grant Thornton, BDO, Mazars, Moore, UHY, Baker Tilly) often offer more personalized service and flexibility.
- Technology & analytics: Many firms are investing heavily in audit-tech (data analytics, dashboards) and new service models for SMEs/start-ups.
- Regulation & quality risk: Firms face scrutiny (e.g., audit fines for PwC/EY in the UK) — clients should evaluate how firms address quality and regulatory compliance. (accountingweb.co.uk)
- International network importance: For clients operating cross-border, network membership (e.g., Moore Global, Baker Tilly International) matters for consistency of service globally.
- Location & infrastructure: London addresses reflect prestige and client-facing capacity; London remains a hub for headquarters of many of these firms.