Two students will attempt the 8,000-mile drive of a lifetime when they set out to get from London to Mongolia in a cheap old banger painted to look like a cow.

Duncan Bucknill, 20, from Chiswick, and Patrick Cronin, 21, from Acton, are taking part in the Mongol Rally 2006, which leaves Hyde Park on July 22, to raise over £2,000 for two charities Send a Cow and the Christina Noble Foundation.

The friends will be hoping to avoid breakdowns as they line up alongside 200 other cars hoping to battle their way through Europe, Russia, Kazakhstan and Kyrgyzstan before reaching their final destination of Ulaan Bataar, the Mongolian capital.

They hope to complete the journey in around four weeks and are travelling under the moniker of Team Dairy Devil. They have even created a motto for themselves - Who Dairys Wins.

Patrick, who studies mechanical engineering at Bristol University, has a few worries about the trip. He said: "Our car goes 50mph tops. We bought it off eBay for £300. It did eight miles before it broke down! We are trying to fix it so that it will actually make it.

"There is absolutely no back-up. You are on your own so if you do break down, it's your problem."

But, he said, breakdowns could be the least of their problems. "My parents are a bit worried. They have read the statistics from last year when a couple of people got held up at gunpoint. But they think it is a great opportunity and they know that we can look after ourselves."

Last year, 43 cars started the rally but only 14 reached the finish line.

Mr Bucknill and Mr Cronin have known each other since they were at secondary school together and came up with the idea to take part in the Mongol Rally over "a couple of beers", according to Mr Cronin.

He added: "It's one of those classic things you say you'll do but don't really realise you are actually going to do it. It's a bit crazy."

For more information or to sponsor the daring duo, go to their website dairydevil.mongolrally.com.