Electra Partners, the firm's former owner and another private equity house, announced the deal this afternoon. Bezier's sale has been the subject of speculation since May when The Times ran a story putting a 100m price on the group.

Graham Thomas, MidOcean managing director, said in the statement that bezier would be "an enviable asset for MidOcean".

"Market trends have shown a shift from above-the-line to below-the-line advertising. In particular we have identified POP has a high growth market and so we are delighted to now own the market leader in this sector.

"I am confident this will be a prosperous and exciting partnership for both bezier and MidOcean Partners now and into the future."

Mark Shaw, formerly Bezier managing director for its Wakefield site, has been promoted to group chief executive

He said: "This is a fantastic finish to what has already been a brilliant year for bezier. New investment is recognition of our incredible potential and recent achievements including a target-busting turnover of over 60m and expansion into two new sites.

"It is also great news for our colleagues. There will be some structural changes to senior management roles, [but] colleagues will be largely unaffected by this sale and ambitious targets for continued growth and expansion mean great new opportunities for new and existing employees."

Bezier has sites in Wakefield, Bristol, Poole and London and employs more than 600 people.

Story by Josh Brooks