Top Accounting Firms in UK

October 14, 2021 by Admin

The UK is known for being the birthplace of some of the biggest accounting firms in the world. But just which accounting firms are the biggest and best? Below is a guide to some of the top accounting firms in the UK.

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Deloitte was founded in 1845 in London. The company now has offices in over 150 companies and is the biggest of the accounting ‘big four’ by quite a large margin – taking in a global annual revenue close to $50 billion.

Although headquartered out of the USA nowadays, the firm still has a strong hold of the UK market. Richard Houston is CEO of Deloitte UK, which continues to be ran from a London HQ. The firm owns 50 offices located across the country and hires roughly 20,000 UK employees.

Deloitte caters to a vast range of clients across the UK. Famous big UK clients include GlaxoSmithKline and BP.


PwC (aka PricewaterhouseCoopers) is a UK-based accountancy firm with an international client base. The firm’s history can be traced back to the 1850s when William Cooper first set up his accounting firm in London. This company would later merge with Price Waterhouse to create PricewaterhouseCoopers.

PwC has its headquarters in London. The firm’s global revenue is thought to be $43 billion. Bob Moritz is the chairman of PwC. The firm’s UK service consists of 62 offices across the country and 22,600 employees.

PwC’s biggest UK clients include the likes of HSBC and Aviva. The firm caters to a range of industries.

Ernst & Young

Ernst & Young is the third biggest of the top accounting firms in the UK. The company’s roots can be traced back to the 1890s, although Ernst & Young as it is known today was only founded in 1989.

Headquartered in London, Ernst & Young has an international client base and makes an annual revenue of $40 billion. The firm has 21 offices located across the country and has over 10,000 UK employees with many more abroad.

Big UK clients of EY include Aston Martin, Vodafone and Intermediate Capital Group.


KPMG is an Anglo-Dutch accounting firm – it is the fourth biggest within the international ‘big four’. KPMG’s history can be traced all the way back to an accounting firm in Bristol launched in 1818. Various mergers have allowed the company to grow over the years. It now has a global revenue of $29.22 billion.

KPMG’s UK headquarters is located in London. The company employs 14,000 UK employees and has 22 UK offices.

The firm caters to a range of clients from a variety of industries. Top UK clients include Associated British Food and BAE systems.


BDO has its headquarters in Belgium, but serves clients all around the world. Its global revenue is thought to be $10.3 billion.

In the UK, it is the biggest accounting firm not within the ‘big four’. The firm has 18 office locations and roughly 5000 employees. It’s UK headquarters is located in London on Baker Street.

BDO caters to a range of industries and serves clients of all sizes. It has the most audit clients of any UK accounting firm.

Grant Thornton

Grant Thornton is another international accounting firm and it is currently the 6th biggest in the UK. Its origins can be traced back to an accounting firm in Oxford named Thornton and Thornton. It would later merge with US accounting firm Alexander Grant & Co to create Grant Thornton.

Grant Thornton’s headquarters is located in Finsbury Square in London. The firm employs more than 4,200 UK employers.

Back in 2018, Grant Thornton exited the audit market for big UK companies, focusing on more mid-range companies. Its services cater to a range of industries.


RSM is an accounting network formed of RSM US (formerly McGladrey) and RSM UK (formerly Baker Tilly LLP). The RSM UK arm is currently the 7th biggest accounting firm in the UK.

RSM UK’s headquarters is located in Farringdon St, London. The firm employs 3,650 UK staff and owns 35 offices around the country.

The firm takes on clients from a range of industries at all levels. It has won a number of awards in recent years.

Smith & Williamson

Smith & Williamson was founded in 1881 in Glasgow and opened its first London office in 1893.  Via various mergers, it has grown to become one of the biggest independently owned accounting firms in the UK.

The firm has hired around 1,700 employees and has 11 offices around the UK. Their headquarters is located in London.

Smith & Williamson has experience serving clients in a range of industries. On top of general accounting, they also offer services such as investment management and financial advice.


Mazars is a French-owned accounting firm with a huge presence in the UK. It’s global revenue is worth 1.9 billion EUR.

The firm employs 2300 people across 16 offices in the UK. Their UK headquarters is located in Tower Bridge House in London.

Mazars has been a big advocate for joint audits and encourages openness and transparency within accounting. The firm works with a wide range of different types of client.


PFK (Pannell Kerr Forster) is an international accountancy firm that was formed in 1969 as a result of four accountancy firms from Australia, Canada, the UK and the US all merging.

They are a big company within the UK market, hiring over 1,700 employees in the UK across 28 offices. Their headquarters is based in Canary Wharf in London.

PKF offers a range of financial services to various industries. They are dedicated to preparing companies financially for the future.

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