After a shuddering performance across the global economy ensured a slow recovery for UK law firms from the financial crisis, the 2013-14 financial year signalled a return to health for many firms. As the initial results from the UK's 50 largest firms by revenue dripped in this time last year, they largely reflected a picture of positive performance, with combined revenue across the group climbing to a high of nearly £14bn. Average growth, meanwhile, was almost on a par with that seen in 2007-08 – shortly before Lehman's crash – and revenue per lawyer figures based on these pre-audited results indicated that firms' cost-cutting initiatives were bearing fruit.

However, beyond headline revenue figures it is becoming increasingly difficult to measure the success of leading law firms. A progressively diverse and expansive international footprint, near-shoring ventures, affiliated consultancy businesses and the introduction of large ranks of fixed-share partners as a result of recent tax rule changes will all have a role to play in fluctuating top-line numbers over the coming years.

As partners such as Dentons chief executive Elliott Portnoy have argued, average profit per equity partner (PEP) no longer – if it ever did – paints a complete picture of the health of a global law firm.

Against this backdrop, Legal Week's annual analysis of the accounts of the UK top 50 commercial law firms, in association with Smith & Williamson, looks at the overall performance of the country's top firms based on a variety of metrics. So does the return to form suggested by last year's climbing revenues reflect the underlying health of the largest firms.

Smith & Williamson's data was compiled using the consolidated accounts of the limited liability partnership (LLP) containing each firm's UK partnership. Within Legal Week's top 50 Slaughter and May, Mishcon de Reya and Osborne Clarke have not converted to LLP status so are not included in this analysis.

Figures for firms that operate a verein structure, including DLA Piper, Norton Rose Fulbright and Hogan Lovells, do not show full global performance or costs.

Recent mergers and consolidation also have an impact on overall averages; for example, 2012-13 figures for Herbert Smith Freehills represented just seven months of trading, following the tie-up between legacy Herbert Smith and Australia's Freehills in October 2012, affecting comparisons with the following year. Meanwhile, Ashurst's financial integration with Australian partner Blake Dawson is only partially reflected given it occurred on 1 November 2013; similarly, the 2013-14 accounts filed by legacy Wragge & Co and Lawrence Graham pre-date the firms' 1 May 2014 union. For reference Lawrence Graham has been included in this table, even though it was not in our top 50 last year.

Sticking with headline metrics, revenue across the group grew by 6.8%, with average fee income increasing from £268.1m in 2012-13 to £286.3m in 2013-14. Nine of the firms saw a dip in fee income, of which Ince & Co's drop of 5.8% to £86.4m was the greatest.

Giles Murphy, head of professional practices at Smith & Williamson, sounds a note of caution despite the growth: "The big question is, is this off the back of firms' strategies or simply economic recovery? Firms in general are marginally more efficient than they were pre-recession, but I suspect a vast amount of this improvement comes from a more benign economic environment."

Ranked by fee income per lawyer, Allen & Overy (A&O) comes out top, with its lawyers generating an average of £554,000 against a magic circle average of £514,800 and a group average of £297,700. Parabis, with its volume-based model, falls at the lowest point on this scale, with its lawyers making an average of £92,000. TLT is the only other firm where fee earners on average bring in less than £100,000 each.

"The 2013-14 financial year covered the tail end of the tough times and about six months of the beginning of the better times," comments A&O finance and operations director Jason Haines. "Because of their operational gearing law firms' bottom lines are very sensitive to fluctuations in the market, but our people have done really well in tough conditions."

• Hogan Lovells and CMS become two of 13 UK top 50 to sit debt free as group cuts borrowings by 9%
• 'The fascination with PEP is putting firms at risk' – lessons from the UK top 50′s accounts
• Beyond PEP: why you need to look deeper to find meaningful comparisons of law firm performance
• The age of specialism – investing in your strengths is a prerequisite in today's market

Turning a profit
Operating profit figures show the top 10 firms by fee income in 2013-14 are also the most profitable. Lower down the revenue rankings though there are large fluctuations in profitability as the impact of investment decisions played its part for some firms. Three in particular – Ince & Co, RPC and DAC Beachcroft – saw a sizable drop in profitability over the year.