The consulting sector, which includes the Big Four – Deloitte, EY, KPMG and PwC - saw the fastest growth in 2020-21, with revenue almost doubling year on year, according to analysis by Tussell.

The Big Four earned £1bn from consulting fees for public sector organisations in 2020-21 and was the fastest growing sector.

The UK Strategic Suppliers Report, which examines the UK public sector revenue earned by strategic suppliers, found that revenue increased by 24% in the 12 months to September (2020-21).

In the consulting sector, which was dominated by the Big Four accounting firms, a total of £1bn was earned in 2020-21, up 91% on the previous year.

Deloitte earned more than £599m over this period, up from £242m, jumping from 25 (2019-20) to 10 in the ranking (2020-21).