Mark Rigby will own the company alongside chairman Bruce Brown and national head of investment Ezra Nahome after agreeing terms with consultancy WS Atkins.

The deal, which is backed by Bank of Scotland Integrated Finance, is worth £46.5 million. On completion £40 million will be paid in cash with the balance satisfied through the issue of a vendor loan note, which will be interest-free for three years.

On top of this sum is an earn-out of £10 million, conditional upon the financial performance of the acquired business in the year to April 2008.

The disposal is part of Atkins’ strategy of focusing on its core activities, with the proceeds to be reinvested in the business. Atkins expects to make a profit of £20 million from the sale assuming no additional payments are made under the terms of the earn-out.

The deal is scheduled to be completed at the end of the month if regulatory approval is granted.

Lambert Smith Hampton has 950 employees across the UK and Ireland. In the year to April 2007 it generated revenues of £81.8 million, and its profits before tax were £9.3 million, up 90 per cent on the previous year.