Clydes leads top 20 revenue rankings over five years after Barlows merger, with Bird & Bird close behind

DWF, Kennedys and Mishcon de Reya have emerged as the fastest-growing firms in the UK top 50 over the past five years, according to research compiled by Legal Week.

The data shows that the trio have significantly outperformed their rivals in terms of revenue growth, with all three firms seeing turnover rise by more than 150% over the period between 2006-07 to 2011-12. This compares with an average revenue increase of 40% across the top 50 as a whole.

Expansive DWF has seen the largest increase in turnover over the period, with revenues climbing 159.5% from £39.3m to £102m following a series of mergers and team acquisitions.

Turnover rose by 22.9% during the last financial year alone, with DWF adding Newcastle insurance firm Crutes in January and Manchester private client boutique Lane-Smith in May 2011.

Meanwhile, Kennedys has seen turnover grow by 155% over five years to £109.1m on the back of a similar spate of mergers and acquisitions.

In July 2010, it took over the Sheffield office of defunct firm Halliwells, while last year it merged with both its Dublin and Portugal alliance firms.

In contrast, Mishcons achieved its 152.1% rise in revenue to £73.1m organically.

Mishcons board member James Libson (pictured) said: "In the first two years of the last five-year period, we had little or no growth. It was at the start of our current three-year plan that we really went for it and hired people and saw revenues shoot up."

Looking solely at the 20 largest UK law firms by revenue, Clyde & Co has seen the biggest turnover growth over the five-year period on the back of its merger with Barlow Lyde & Gilbert last November, with the tie-up helping revenue grow by 112.6% to £287m.

Clydes was followed by Bird & Bird, where organic growth has taken revenues up 103.3%, with DLA Piper's international arm – buoyed by its recent merger in Australia – Norton Rose and Berwin Leighton Paisner making up the rest of the top five.

By profits per equity partner (PEP), Kennedys has seen the biggest increase across the top 50 as a whole at 49.4%, followed by DWF and Eversheds. Looking at the 20 largest firms, the biggest increases in PEP were at Eversheds, Freshfields and the UK arm of Hogan Lovells.

At the opposite end of the scale, Ashurst has seen the biggest fall in PEP in the top 20 over the past five years, with profits dropping 22.2% to £744,000 over the period, closely followed by SJ Berwin and Addleshaw Goddard.

In terms of revenue, Simmons & Simmons, Addleshaws and SJ Berwin were the worst five-year performers in the top 20.

Addleshaws senior partner Monica Burch said: "[Our slower rebound] could be partly due to the fact that, until recently, we were almost wholly reliant on the UK market whereas a number of our competitors had that international base.

"Our focus though is not on the past, but on looking forward and delivering year-on-year improvement."