John Pickering, the group chief executive of Irwin Mitchell, is to leave the firm.
His successor, Andrew Tucker, who was previously chief executive of Irwin Mitchell’s personal legal services (PLS) division, will work closely with Pickering over the next few weeks in a transitional period for the firm.
Pickering became group chief executive in 2011, and his decision to step down brings to a close a successful 37-year career with the firm which he joined as an articled clerk.
Irwin Mitchell’s Chairman Glyn Barker paid tribute to him as " a leader and inspiration to the firm as a whole".
Pickering said his decision to step down was based on the changing legal sector and his desire for Irwin Mitchell to have a settled senior management in to drive its strategic growth and corporate development plans.
He will pursue long-held ambitions for holding non-executive director positions within other businesses.
The news comes after a successful 18-month period for Irwin Mitchell in which it exceeded £200m in income for the first time, completed five acquisitions, and announced it would open its ninth regional office in Southampton this year.
"Having put in place a top class executive team, John believes that the firm should now be led by a chief executive who will lead the organisation over the medium term. Although I personally will miss John a great deal, this is an honourable decision, taken in the long term interests of Irwin Mitchell, and John has my full support," said Barker.
"This has been a difficult decision for me because I am deeply committed to the firm. I am proud of its growth, development and success, something which has been derived from the hard work of many people over the years," said Pickering.
"I believe we have created a basis for the future success of the business. It is well placed to take advantage of all the opportunities which will come our way in the near future and to progress our plans.
"Andrew is the right man for that task and I am pleased the Board has appointed him. I am confident he can lead the firm to success and even greater things in the future," he added.
Andrew Tucker joined Irwin Mitchell as a solicitor in 1985 and became a Partner in 1988. He first became a Board member in 1999 and then led the firm’s personal injury division from 2009. He became chief executive of PLS in May 2011.