Law firms outside the top 25 in the UK are growing at a faster rate than those inside the top 25, new figures have revealed.

Research by Deloitte into the first quarter of 2012/13 found firms between 26 and 50 grew fee income by 4.5%, whilst those from 51 to 100 increased their revenue by 5.5%. In comparison, the bigger firms were more sluggish, the top 10 recording just a 1.7% increase and those from 11 to 25 growing turnover from fees by 2%.

Overall the UK’s top 100 law firms recorded fee income growth of 3.8%, marginally less than the same period in 2011 and the slowest rate of growth since the quarter ending 31 January 2011.

Across the top 100, chargeable hours per fee earner increased by 0.7%, with fees per earner up by 1.5%.

Jeremy Black, partner in Deloitte’s professional services group, said the relative success of firms outside the top 25 suggested that their rates were under less pressure than at the bigger firms.

On average, the top 100 firms had predicted before the start of this year that they would record 4.9% fee income growth in 2012/13.

Black said: ‘Overall firms expect to see some fee income growth in 2013. However, ongoing instability in the eurozone area and the sluggish world economy continue to dominate the business agenda, and it seems unlikely there will be any significant growth in the sector as a whole in the medium sector.’