Litigation powerhouse Quinn Emanuel has posted a mixed set of financial results for 2013, despite firm-wide earnings rocketing to a record high.

However, the firm's 11-partner City office recorded its first annual decline in revenue and profit since its 2008 launch, Legal Week can reveal.

Fee income at the firm's London office fell 28% to £19.8m, while operating profit was 33% down, standing at £12.4m.

Quinn Emanuel said the fall reflected the settlement or coming to trial of three major pieces of litigation for clients Oleg Deripaska, Unicredit and Derek Quinlan in 2012. In that year, the office's revenue stood at £27.5m and operating profit at £18.4m.

"It is impossible to replace such significant matters overnight, especially given our relatively small scale in London," said London co-managing partner Richard East (pictured), who acknowledged the cases made up a substantial proportion of London office revenues in 2012.

Despite the drop, East said the office took on a number of major arbitration and litigation matters in 2013, including several on a contingency basis.

The year also saw the recruitment of Herbert Smith Freehills litigation partner Ted Greeno, and the addition of arbitration head Stephen Jagusch in January, after a protracted exit from A&O.

"We knew that 2013 would be a transitional year for us, but we feel we are in a uniquely strong position to capitalise on our investments in London in 2014 and we look forward to another year of growth."

The financial results halt successive years of growth for the London operation, which saw an 85% leap in turnover between 2010 and 2011, following a 63% jump in 2010.

Away from London, global revenue at Quinn rocketed from $852.5m (£510.9m) to $972.7m (£582.8m) last year, a 14% rise, while profits per equity partner (PEP) grew 1% to $4.48m (£2.69m). Both figures are the highest ever recorded by the firm.

The smaller increase in PEP, compared to revenue, was partly due to a number of investments by the firm – including several senior partner hires in the Europe and US – and office openings in Sydney, Munich and Hong Kong.

Quinn also launched a Brussels base last month.