Sir Michael Darrington has a body mass index of 23.5, which makes him the ideal weight for his height.

For a man whose typical lunch consists of a sausage roll and a cheese and onion pasty from Greggs, the company he has led for 24 years, he is surprisingly slim. “I think it's fine to have a jam doughnut and a sausage roll a few days a week,” he says. “As long as it's part of a healthy diet.”

As the Newcastle-based bakery group yesterday announced a healthy rise in pre-tax profits, it also said that a search had begun for a successor to its 66-year-old managing director.

Although Sir Michael has been persistently dismissive of his advancing years, remarking a few years ago that he could “hardly fail to notice that the new Pope is 78”, Greggs yesterday acknowledged that the time had come to trade in the MD for a younger model.

Sir Michael, or plain old Mike Darrington - as he still is to many - has beaten the drum for the northeastern high street baker since he joined the company in 1983, two years before it was floated.

Although he is often pictured shovelling short-crust pastry into his mouth, surrounded by workers in hairnets, his background is not quite that of your typical Greggs customer.

Educated at the exclusive Lancing College, the West Sussex boarding school, he began his career in the City, training as a chartered accountant.

After qualifying, he joined United Biscuits, initially in a financial role, but, after a four-month course at the Harvard Business School, he moved into general management, taking up a role as managing director of Sayers, a loss-making Liverpool baker with some 120 shops.

After 17 years with Sayers, he made his foray into the world of steak bakes, pies and pasties, joining Greggs as group managing director in 1984.

Greggs makes a big play of its culture to “put something back” into wider society. Indeed when Sir Michael was knighted in the 2004 New Year's Honours List, his citation was equally for services to the community as to business.

Under Sir Michael the company gives 1.4 per cent of profits to charity each year, and has set up more than 120 breakfast clubs in the UK's poorer areas, to give schoolchildren a healthy start to the day.

He is married to Paula, with whom he has a son and two daughters, and lives in the Northumberland countryside. Sir Michael lists his interests as sailing, golf, reading, and, worryingly, pyrotechnics. He also likes sausage rolls.