An increase in hourly rates has helped drive fee income at the UK's top 10 firms up 6.3% this quarter compared to the same period last year.

A growth in headline rates was the primary driver behind the rise in turnover at the leading firms in Q2, according to Deloitte's latest quarterly survey. 

By contrast, firms in the 26-50 bracket by revenue achieved growth of 6.7% primarily through increases in headcount.

As a whole the UK's largest 100 law firms by revenue have posted average fee income growth of 5.2% during the second quarter of 2013-14. 

Deloitte professional practices partner Jeremy Black (pictured) said: "The results support signs of recovery in the wider economy. However, the results are massively divergent – some firms are finding it tough, especially those without an international footprint, as the domestic market remains particularly competitive. 

"Firms operating in a volume space are also finding it difficult, while those in the value space are finding it easier."

The uplift paints a healthy outlook for the top 100, which has forecasted an average growth rate of 6% for the 12 months leading to April 2014 and an 8.4% increase in year-on-year numbers for Q3.

Corporate heavyweights have pointed to growing business confidence on the back of increased activity in the IPO and transactional spaces.

Allen & Overy London head of corporate Richard Browne said: "For us, the situation has improved far more strongly than we expected this time last year. We are seeing increased confidence from clients, we are working on larger deals and there is strong flow in the equity markets and more IPO work."

Clifford Chance corporate partner Patrick Sarch added: "There is momentum in the market and we are confident it will be maintained. There is more confidence in the boardroom and there are increasing levels of spending. All firms are also seeing an uplift in regulatory enforcement work, which was expected after the crisis, and litigation has continued to increase work volumes."