Despite a strong showing among the UK mid-market, Legal Week's analysis of the 2014-15 financial results reported so far shows combined revenue growth of just 1.6% as euro exposure took its toll on performance.

Results from the 42 top 50 law firms to have released their 2014-15 performance reveal that overall revenue for the group was £16.2bn, a modest 1.6% increase on their 2013-14 collective turnover of £15.9bn. The average revenue across the group crept up to £384.6m from £378.7m.

The stunted growth reflects the impact of currency fluctuations on firms' results in an otherwise resurgent deals market. As a result performance was not uniform across the firms, with the magic circle and many of the more internationally facing firms growing only modestly in comparison to the more  domestically focused mid-market.

Eight firms posted double-digit revenue increases, the biggest of which were at Stephenson Harwood, Macfarlanes and Addleshaw Goddard.

By contrast, the nine firms from last year's top 10 that have announced their 2014-15 results – all of which have significant international businesses – saw an average 0.9% dip in revenue compared to last year.

Across the group as a whole nine firms reported a contraction in revenue, including Norton Rose Fulbright, Ince & Co and DLA Piper. However, while these all saw revenue fall by 4% or more, four of the nine saw turnover decline by less than a percentage point.

This year many firms announced results on a constant currency basis, limiting the impact of currency fluctuations year to year. With the exception of Herbert Smith Freehills, which only reported a constant currency figure, all results analysed take account of currency changes.

Freshfields Bruckhaus Deringer managing partner David Aitman comments: "If I look across all of our offices the underlying pattern was growth everywhere. The measure for us is: did we grow the top and bottom line in each country we're in in the local currency? And on that measure we saw growth of 4-5%. Because we convert at year-end the effect is that instead we saw an increase  of around 1%, but for me that isn't relevant – on a constant currency basis revenue and PEP grew."

Among the top 10 Allen & Overy (A&O) posted the biggest revenue rise with a 4.1% hike to £1.28bn. "A&O is a well-hedged business with a broad geographic reach and practice spread," says managing partner Wim Dejonghe (pictured). "This is what enabled us to deliver an increase in revenue and profits for the sixth year running. We believe we can thrive irrespective of the macro economic conditions."

The overall growth in the market, although not spectacular, continues the year-on-year upward trend since 2009-10.

Eversheds chief executive Bryan Hughes comments: "While we have seen more transactional activity in the last 12 months than we have in recent years, the heady days of pre-recession will never return. Indeed, as we see the number of new entrants to the market increasing, competition, disruption and the need to continually change and adapt is only likely to increase."

Dejonghe also cited the increasingly crowded legal market as one of the challenges facing law firms: "Competition is the biggest challenge, whether that is from traditional players such as the US outfits or alternative providers of legal services such as the Big Four accountancy firms."