Bill Gates, Larry Page, Sergey Brin and Mark Zuckerberg. What do they have in common? The all set up businesses, which are now worth billions, at tender age of 25 or under.

But the Microsoft, Google and Facebook entrepreneurs are definitely not a rare breed. When it comes to young business founders, the under 25 group is growing at a faster rate than any other age group – 15% compared to the 6% increase for older entrepreneurs.

During the first half of this year, 20,700 businesses were started by under 25s. Contrary to what some people believe, the budding young Bransons are not just sitting at home on a computer dreaming up the next MySpace. The most popular sectors are construction, hairdressing, restaurants and leisure, according to Barclays.

The figures paint a picture of a nation fuelled with young entrepreneurial spirit, as increasing numbers of school leavers and graduates decide to set up on their own instead of climbing the corporate ladder as an employee.

Overall, across the age groups, 253,700 new businesses were set up in the first six months of 2007. This compares to 236,300 during the same period last year – a 7% rise in the number of people taking an entrepreneurial leap.

How old were you when you first felt a desire to become your own boss? Let us know in the box below