The first firm to publish its figures in this year's financial reporting season has claimed a record turnover increase for 2006-07.
Fee income at Lincolnshire firm Wilkin Chapman was up more than 13 per cent, taking turnover to above £11m.
The firm saw particular growth in its debt recovery department and a successful marketing campaign targeting public sector organisations.
The firm now claims to act for more than 50 local authorities across the UK while internationally, Wilkin Chapman's criminal and personal injury lawyers represent forces personnel worldwide.
Wilkin Chapman senior partner Philip Day said the firm was "delighted" with the results.
"We know that our clients are very satisfied with us as we survey them regularly and our hourly rates are less than many other local firms," he added. "This is a real landmark for us and reflects the commitment and hard work of our staff on every level."
Wilkin Chapman is a 34-partner firm with seven offices across Lincolnshire and East Yorkshire and a total of 265 staff.