Mitchells & Butlers (M&B) has appointed Alistair Darby, Marston's chief operating officer, as chief executive to end an 18-month search.

Mr Darby has been lured away to take on one of the toughest jobs in the beerage, with the aggressive 23 per cent shareholder Joe Lewis, the billionaire currency trader who has already bid for the company and seen off one chairman and chief executive, peering over his shoulder.

M&B's last chief executive, Adam Fowle, was ousted in March 2011 – just one of more than a dozen boardroom casualties in recent years.

Bob Ivell, the chairman, has been running the company for the last 11 months, and conducted the search for a new chief executive himself, without the use of headhunters.

Mr Darby will join M&B at the start of October, and take over fully following a brief induction and handover period from Mr Ivell, who will revert to a non-executive role.

He is likely to be paid slightly less than Mr Fowle was, with a basic salary of around £500,000.

In addition, he has not been given a golden hello, and will not get special pay-off terms in the event of, say, Mr Lewis launching a successful takeover bid in six months' time.

Mr Darby, 46, has worked for Marston's since 1997. He was previously at Mars Confectionery, Wolverhampton and Dudley Breweries, and United Distillers.

He said: "Mitchells & Butlers is a market-leading business with tremendous potential that is well advanced on a transformation programme. I am excited by the opportunity to lead the company and, together with the management team, to build on M&B's strong estate, brands and operations."

Marston's has not immediately replaced Mr Darby, with the managing directors of its two divisions reporting directly to the chief executive, Ralph Findlay.

Analysts point out that Mr Darby was unlikely to get the top job at Marston's as he is a similar age to Mr Findlay.