Turnover growth by top-100 firms has moved into double figures for the first time since the financial crisis of 2008 - largely because of mergers between firms - an authoritative survey reveals this week.

Latest figures from Deloitte’s quarterly legal sector survey show that in the quarter ended 31 July 2013 firms posted an average 10.5% more revenue than in the same period last year. 

Mergers between firms accounted for half of the revenue increase, with the rest driven by an increase in general market activity. Outside the top 25, turnover grew by 14%.

Jeremy Black, partner in Deloitte’s professional services practice, said merger activity reflected consolidation, particularly in areas such as personal injury. ‘Merger activity continues apace, particularly in the volume space and outside of London where markets remain tough and law firms continue to face a number of challenges. Consolidation outside the top 25 firms has led to significant growth in average fee income and fee earner headcount,’ he said.

‘It’s been a surprisingly strong quarter, even when the merger activity is stripped out, firms saw an average underlying growth of 5%,’ he added.

Income per fee earner rose 4% due to an increase in work and rates. Firms forecast a revenue increase of 5.1% for the financial year 2014.