Overall, the UK consulting market grew almost four times faster than the wider economy in 2015, an increase of 8.2% to £6.79bn.
The financial services sector remains the biggest market for UK consultants and one of the fastest growing, up 14.3% to £2.2bn.
The Big Four’s share of the market is only set to increase as they are well situated to win more risk and regulatory work, according to a report published today by Source Global Research.
“The UK consulting market has seen strong growth across the board, but once again it’s the Big Four that have risen to the top.
"This is largely because clients recognise the scale and scope they can bring to bear, though inorganic growth also plays a big role. A busy regulatory environment, especially in financial services, has further served to bolster the Big Four’s position,” said Fiona Czerniawska, director and founder of Source Global Research.
A boost in public sector consultancy - up 3.7% to £1.25bn - is also set to benefit the Big Four, said the report.
Cybersecurity is also having a huge impact on risk consulting with some firms reporting 40% growth in this service last year.