Norton Rose Fulbright, DWF and Mishcon de Reya have emerged as the fastest growing firms in the UK legal market over the last five years, according to data compiled by Legal Week.

Norton Rose Fulbright is the most striking example of the wave of international and domestic mergers experienced by the top 50 UK firms in the last five years.

The firm has grown by a massive 265% in the past five years, morphing from a top ten UK City firm, to a global player after a series of mergers. In 2010 it merged with Australian firm Deacons, in 2011 it did mergers with South African firms Deneys Reitz and Canadian firm Ogilvy Renault, a further Canadian merger followed in 2012 and then it did a tie up with US firm Fulbright & Jaworski in 2013.

Those mergers have taken the firm's revenue from £307m in 2009-10 to £1.12bn in 2014-15.

DWF has similarly grown through a series of mergers, although these have been more focused on the domestic market. These include its 2011 tie up with Newcastle insurance firm Crutes and 2012 mergers with Birmingham insurance boutique Buller Jeffries and Scottish firm Biggart Baillie. Other major additions include its purchase of Cobbets out of pre-pack administration in 2013 and its merger with professional indemnity firm Fishburns – deals which added roughly 600 staff and took its revenue to nearly £200m.

The firm's appetite for mergers appears to have slackened in the last couple of years, although it did announce earlier this year, that it was merging with £2.5m insurance litigation boutique Watmores – though this merger did not take place until after the 2014-15 financial year end.

DWF managing partner Andrew Leaitherland said: "Having gone through a series of mergers and acquisitions, the last year and a bit has focused on consolidation, bringing those businesses together and making sure the size of platform is right."

By contrast Mishcons' growth has been largely organic.

Of the ten firms that recorded the highest revenue growth over the last five years, Mishcons was the only one not to undertake a major merger during that period. The firm's revenue has increased by 146% over the period, leaping from £47.5m to £116.7m.

Mishcons had targeted reaching revenue of £100m by 2016 in its 2012 three-year strategy, a goal it achieved this year.

The firm has focused on growing its litigation practice, launching a business crime group in 2014 and bringing in heavyweight laterals such as Addleshaw Goddard insurance litigation head Richard Leedham.

Mishcons has also successfully boosted its profit per equity partner (PEP) by a striking 111%, the second largest percentage PEP growth of a UK top 50 firm over the period. Its PEP rocketed from £450,000 in 2009-10 to £950,000 in 2014-15.

City firm Macfarlanes saw the largest increase in PEP over the five-year period. Its PEP increased 119% from £710,000 in 2009-10 to £1.53m in 2014-15. This puts the firm in elite company alongside the magic circle as one of six firms with an average PEP above one million pounds and in second place after Slaughter and May on £2.22m.

Mishcons is now head of the chasing pack, as the firm with the highest PEP below one million pounds.

At the other end of the scale were Ince & Co and Trowers & Hamlins which reported contractions in revenue of 8% and 11% respectively over the five year period.

Ince & Co has been hit by a prolonged slump in the shipping market while Trowers has seen its revenue, rebound this year with a 2.8% uplift, but is still significantly down on its 2009-10 size.

Jan Heuvels, Ince & Co's international senior partner said: "The firm is addressing this downturn in revenue by focusing on a number of key growth programmes, for example, increasing our transactional capacity in our chosen sectors, updating the strategy of each sector group and practice team and undertaking a substantial improvement programme in our business services."