Inspiration for a successful business idea can come from anywhere, but for Jermaine Hagan, it was very much the result of personal need.

Back in his final year at university, the Londoner found that he had little time for revising, or even going to lectures in the first place.

This was because Mr Hagan, now 24 and the founder of popular mobile phone application Revision App, was at the time running a successful clothing business from his student bedroom.

And while his college friends would attend classes and hit the library, he would sit, surrounded by boxes, and spend hours putting jumpers and other clothes into parcels, ready to be posted out to customers.

With exams looming, Mr Hagan's only hope of passing his degree was to borrow his friends' revision notes. Thankfully they agreed, and he was able to graduate from London's Brunel University.

He says: "It gave me the idea for Revision App. I realised that there must have been thousands and thousands of other students out there in the same situation... desperate for better revision notes.

"And in this day and age, everyone spends all their time on their mobile. So I thought, 'Why not gather as many revision notes as possible and turn them into an app on your smartphone?'"

'Hustling'

Armed with a degree in financial computing from Brunel University, Mr Hagan had the skills and knowledge to be able to produce the first basic test version of the app.

He filled it with all the notes that he had been able to gather from college friends, both those on his course and those doing other subjects.

"I was literally hustling to get the content," says Mr Hagan.

But, aware that he didn't know how to successfully market a mobile phone app, Mr Hagan decided to learn by getting work for companies that do just that.

"I thought, 'Why don't I try and get paid while I learn?' so that was what I did.

"You just have to get in the right place, and I've always been super-confident. I learned on the job as a consultant for some of the largest mobile app development firms."

And realising that he also needed to improve his wider business skills, instead of paying to get the classic business qualification, an MBA or Master of Business Administration, Mr Hagan successfully applied for a job with carmaker Honda.

Working for a year at Honda's European headquarters, located just outside London, he says it gave him vital knowledge on pricing and profit margins.

A few years earlier, Mr Hagan had done the same trick to get the skills he needed for his clothing company, doing an internship for a large clothing retailer.

'Global domination'

When he was happy that he had all the knowledge he required to start Revision App, Mr Hagan launched the business in November 2010. Since it took up all his time, he had by now closed the clothing firm.

Instead of relying on notes from his old friends, Revision App pays a team of teachers to help produce content that applies directly to national school curriculums and college courses.

Mr Hagan says this is vital "to give parents complete reassurance".

Revision App was an immediate success and has since grown to have more than one million UK users.

And while Mr Hagan won't release any financial details, Revision App is today one of the most downloaded education applications in the country.

It applies a "freemium" model, under which the app can be installed for free and users don't have to pay for basic content. Revision App then makes its money by charging people to view its educational videos, along with other more advanced or in-depth resources.

Mr Hagan launched Revision App with his own savings, but he has since secured some outside investment, as well as funding from the government's Start-Up Loans scheme.

Based in east London, and with 10 permanent staff, Revision App is now expanding into Europe and the Middle East, with North America set to follow.

Mr Hagan calls his plans for overseas expansion "global domination".

'Make learning fun'

Such has been the success of Revision App that last November, Mr Hagan was declared young entrepreneur of the year by Shell Livewire, the young business support service run by oil group Shell.

Mr Hagan was also invited to address the 2013 Conservative Party conference.

He says: "I have always liked working and making money.

"Prior to the clothing business at uni, I used to sell CDs and DVDs on eBay while at school. And after that, I used to write business plans for entrepreneurs."

Raised in "a working class family" in north west London, Mr Hagan says his parents "brought me up to be ambitious".

He adds: "I'm trying to strive for greatness... I get by on four hours' sleep a night - relaxing and me don't really go together.

"And anyway, what I'm doing at Revision App is so enjoyable - we are trying to make learning fun.

"We want children and young people to use Revision App on their phone instead of Angry Birds [or other non-educational games]."