Herbert Smith Freehills' (HSF's) bank borrowings grew by 38% for 2012-13, as the firm's UK fee income dipped by 1.6%.

The firm's latest limited liability partnership (LLP) accounts, the first to be filed since legacy Herbert Smith and Australia's Freehills merged in 2012, show that total bank borrowings increased by more than £30m, rising from £80.2m to £110.7m

Meanwhile HSF more than doubled its bank overdraft, with the facility growing from £26m to £62.7m during the year.

A spokesperson for the firm said: "Our debt levels are in line with the operations of a firm which following our October 2012 merger is nearly twice the size of legacy Herbert Smith and in a period of significant investment including a range of integration projects, and expansion focused on our new offices in New York, Seoul, Frankfurt and Berlin.

"They are structured to meet our requirements over a number of years and are consistent with what we would expect at this point in our trading and investment cycle."

The report, which does not account for the Australian business, shows that legacy Herbert Smith brought in fee income of £366.8m, down by 1.6% on the previous year when it made £372.8m.

Operating profit increased to £107.7m from £101.8m, with profit available for division among the firm's members rising by 103% from £10.99m to £22.4m.

Meanwhile, the top earner at the firm took home £2m during the year, compared with £1.6m in 2011-12.

The average number of fee earners grew 9.6% from 228 to 250, while overall staff headcount increasing by 8% to 372. The figures accompany a slight drop of 1.6% in average member numbers, which fell to 185.

Last June, the firm disclosed combined post-merger revenue of £471.2m for the seven months leading from October 2012 to April 2013.

The firm's partnership last month approved a new pay structure for the combined business, which will come into effect at the start of the next financial year. It will operate a single managed lockstep that will run from 43 to 100 points.