Mayer Brown and Covington & Burling have both posted increases in global revenue, becoming the latest US-headquartered firms to post financial figures for the 2013 calendar year.

Of the two, Mayer Brown saw the greater overall rise, including a 5% revenue spike on 2012 to $1.15bn (£691m).

Net income also grew 13.7% to $345m (£207m), resulting in an 11% rise in profits per partner to $1.29m (£775,000). Revenue per lawyer also grew 4% on 2012, reaching $780,000 (£469,000).

For partners at the firm, the results mark a welcome reversal in fortunes, after revenue tumbled to a six-year low in 2012.

Although the firm does not breakdown revenues by office, London managing partner Sean Connolly said UK revenues had grown by 12% year-on-year in the City.

He singled out the litigation team as having had another strong year, with the finance and employment departments also performing well.

"Last year was the product of what we were doing in 2012, in terms of identifying the right mix of laterals to join the office," he added.

Last autumn, the London office brought in seven new partners in as many weeks, including A&O employment partner Stefan Martin, Berwin Leighton Paisner's Trevor Wood and White & Case's Mayank Gupta.

Separately, Covington saw a more modest increase in global revenues for 2013 to $656.9m (£394.6m), up from $650m (£390m).

In London, firm revenues rose 8% to $60m (£36m) in 2013, with the office partnership growing by one to 26 and the non-lawyer headcount by four to 54, resulting in a raw London revenue per lawyer figure of $750,000 (£450,500).