National firm DWF has defied industry expectations to increase operating profit by 30%.
In annual accounts for 2013/14 filed with Companies House today, the group said profit rose from £39.6m to £51.5m. Turnover jumped from £143m to £189m over the course of the year.
The accounts, taking the firm up to April 2014, are the first reported since acquisitions and mergers in 2012/13 - the most high-profile of which was the pre-pack buyout of national firm Cobbetts in February 2013.
Chairman Alan Benzie, introducing the accounts, said the performance proved to any doubters that the firm is not a 'flash in the pan'.
Benzie said: 'Many people in the legal profession are looking to see whether we're going to trip up. They have been surprised at the speed, scale and sustainability of our growth.'
The firm, which now operates from 12 offices across the UK, increased headcount by 37% over the course of the year to April 2014. Average staff numbers were 2,108 in 2014 compared with 1,537 in 2013 - with legal staff up from 864 to 1,224.
Staff costs increased at the same time, leaping by 36% to almost £86m.
The equity partner with the highest entitlement to profits was paid £1.14m - compared with £1.09m the year before.
The group increased bank loans and overdrafts from around £16m to more than £27m, with net debt rising from £13.5m to £23.6m.
Following on from the merger activity of 2012/13, which also saw deals tied up with Scottish-based practice Biggart Baillie, Birmingham firm Buller Jeffries and professional indemnity practice, Fishburns, the firm added 39 lateral hires across the business in 2013/14.
Benzie said the ambition remains to break into the UK's top 15, with further mergers and lateral hires 'where appropriate'.