Ashurst saw operating profit drop by more than 20% during 2015-16, after a challenging year in which the firm made significant investment in new premises and IT systems, the firm's limited liability partnership (LLP) accounts show.

Operating profit fell by 21% from £193.1m to £152.1m, while net profit fell 22% from £186.6m to £144.8m, as revenue dropped 10% from £560.9m to £505.2m.

The accounts, which were filed at Companies House this month, state that the firm "entered into finance leases and other financing transactions in respect of assets with a total value of £12.7m".

Cash at bank and in hand fell from £28.7m to £15.8m, while the value of tangible assets doubled, up from £34.5m to £69.9m.

The year saw the firm invest in new premises and IT infrastructure projects, including a move into new premises in Sydney, with money also spent on new practice management and business intake systems.

The accounts show Ashurst's top management team took home £9.4m last year, a drop of 8% from the previous year's figure of £10.3m. The firm's highest paid partner took home £1.09m, up from £1.01m in 2014-15.

The firm paid out £189m in salaries during the 2015-16 financial year – a slight dip of 1% on the previous year's figure. The average number of people employed by the firm grew from 2,651 to 2,722, although total fee earners fell from 1,399 to 1,368.

The results mark a second year of declining figures for Ashurst, which posted single-digit drops in revenue and profit per equity partner (PEP) for 2014-15. It means that since 2013-14 PEP has tumbled by 24.7%, with revenue declining by 14%. The PEP figure the firm posted for 2015-16 is the lowest at any point since 2004-05, when it stood at £567,000.

The filing follows a turbulent 12 months for the firm, which has suffered a number of partner departures including several office heads. In December last year, the firm overhauled its profit distribution system in a move that means partners will receive a single profit payment each year.