Mr Hunter has expressed a commitment to tackling poverty

The son of a grocer, he began his career by selling trainers from the back of a van.

This led him to build up a chain of sports shops which he sold to JJB Sports in 1998, making over �250m.

By 2006, the Sunday Times Rich List ranked the Ayrshire-born tycoon as the richest man in Scotland.

He has given away millions of pounds to charities including Live 8 and the Make Poverty History campaign.

Knighthood

His promise on Tuesday, to give away �1bn to charity, is the largest single sum he has pledged and is thought to be the single most generous philanthropic commitment made by any Briton.

His pledge is only the latest in a long list of charitable donations.

He and his wife Marion set up the Hunter foundation in 1998 to support educational and entrepreneurial projects.

Sir Tom plans to donate at least �100m through the foundation. He gave �1m to the BBC's Children in Need appeal in 2006 and a further �1m to Comic Relief in 2007.

His largesse has also extended to Bob Geldof's Band Aid 20 single, which received �7m of his fortune.

And he pledged �1m in aid to help rebuild schools destroyed in the Indian Ocean tsunami disaster.

The entrepreneur said he wanted his money to go towards the creation of an early warning system in the region.

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He was one of the prime supporters of the Make Poverty History campaign and urged world leaders at the G8 summit in Gleneagles in Scotland in 2005 to use their power and influence to eradicate poverty.

Sir Tom also joined forces with former US president Bill Clinton and pledged an initial $100m (�60m) to the Clinton-Hunter Development Initiative to support developing communities.

The initiative's projects have included sending heart monitors and operating theatre kit to hospitals in Malawi.

His charity work and commitment to tackling poverty earned him a knighthood in the 2005 Queen's Birthday Honours List, for services to philanthropy and entrepreneurship.

Mining village

His immense wealth came from the Sports Division chain of sports shops, which he founded in 1984 and sold to JJB Sports in 1998.

The tycoon has continued to accumulate wealth through the West Coast Capital private equity partnership he founded in 2001.

Over the last year he has acquired Wyevale Garden Centres and Blooms of Bressingham garden centre chain.

In April this year, Sir Tom was declared to be Scotland's first home-grown billionaire.

Ranking the 60th richest person in the UK, the tycoon is thought to have amassed a fortune of about �1.05bn.

He grew up in the mining village of New Cumnock in Ayrshire, before attending the University of Strathclyde.