A teenager who became an overnight millionaire has promised not to rest on his laurels after selling his mobile phone app to internet giant Yahoo for an estimated £20m.

Seventeen-year-old Nick D’Aloisio created Summly – which summarises news stories from popular media outlets – aged just 15.

The app will now close and Nick, a pupil at King’s College School, will work for Yahoo using Summly’s features in mobile products.

The teenager said: “I came up with the idea when I was studying for my mock exams in 2011.

“It was the realisation that Google and other media organisations have loads of information on them, but no way of ordering or summarising them.

“I never expected any of this to happen though – I never set out with this in mind. When I first started creating apps it was just a hobby.

“Now I would love to have the opportunity to do it all over again while working with Yahoo.”

But Nick, who is now one of the world’s youngest technology millionaires, admitted Summly’s rise was not without hitches along the way.

He said: “Like all businesses, we have had our fair share of ups and downs.

“Obviously being young brings certain challenges as well, but I have always tried to learn from the experience.

“To be honest, making money from the app was never the goal and wasn’t really given much thought until we started to attract a number of high-profile investors.”

Summly’s predecessor, called TrimIt, launched in July 2011, which led to a £160,000 investment from Chinese billionaire Li Ka-Shing’s venture capital firm Horizon Ventures.

Further investment followed from the likes of Stephen Fry, Yoko Ono and American actor Ashton Kutcher, allowing Nick to develop Summly.

Once the takeover has gone through, the teenager will work for Yahoo from their Soho office while studying in the evenings to complete his A-levels, after six months away from full-time education.

He said: “It has been a crazy time, but an exciting time.

“It is a real testament to King’s College and my parents for all the support they have given me.”