Sean Phelan may just have pinpointed the answer to a problem that has stumped Microsoft’s brightest engineers: how to deliver useful digital maps to mobile phones.

The North Londoner, who founded Multimap 12 years ago, is said to have first displayed his entrepreneurial streak at school where, at the age of 11, he ran a business peddling stink bombs to his peers.

Yesterday, seveal decades on from those first steps in commerce, Mr Phelan, 49, sold his business to Microsoft, the world’s largest software developer, for a sum thought to be about $50 million (£24.4 million).

As owner of just over half the company he stands to bag $25 million. He can also look forward to a lighter workload.

Mr Phelan says that he founded Multimap as “a classic boot-strap start-up” with less than £100,000 earned through a year’s work with Yankee Group, the technology consultants. From running Multimap as a “one-man operation” for several years he progressed to working “standard five-day weeks” after hiring a professional management team.

From today he will step into the office for a total of eight days a month.

The roots of this rare British technology success story can be traced back to a former stalwart of the British technology scene.

Mr Phelan was sponsored by Marconi to study engineering and computer science at Sussex University.

He has said that his moment of epiphany came several years later when, at the age of 30, the software company he had moved on to required a bail-out from a white knight investor.

The man sent in to turn his employer around was only one year older than Mr Phelan – but he had an MBA.

Mr Phelan, convinced that he was underqualified, moved to France to study for one himself.

Now Multimap’s consumer website trails only Google Maps in the United Kingdom and attracted more than four million vistors last month. It is active in more than 40 countries.

Born into a family of entrepreneurs – his father owned a catering company, while his mother ran a ballet school – Mr Phelan likes to play down the importance of computer code and complex hardware.

“Multimap is not really about technology,” he says. “It has been about developing a company – 120 people – who care passionately about what they do.”