The pair's balloon will be 1,295 feet tall

The current height record for a balloon journey stands at 114,000 feet (34,747 metres).

It was set in 1961 by two American navy officers, following a launch from an aircraft carrier in the Gulf of Mexico.

Three cosmonauts from the Soviet Union tried to better this in the 1970s and succeeded in reaching 118,000 feet (35,966 metres).

Unfortunately, all three men died during the descent and the record was declared null and void.

The balloon Elson and Prescott will be travelling in will be a total height of 1,295 feet (395 metres) -that is seven times the height of Nelson's Column.

At the proposed altitude, their space suits will have to withstand extreme pressure and temperatures as low as -73 degrees Celsius.

"Why are we doing this? It's an unashamed adventure

Colin Prescott

The Russian-designed suits will also have to withstand cosmic radiation bombarding them on the fringe of space.

Elson and Prescott said they have fancied the challenge for a while. Two years ago they took cosmonaut training in Moscow ready for an attempt like this.

Andy Elson, a hot-air balloon designer, is no stranger to peril. In 1999, he was rescued after ditching in the sea near Japan during a round-the-world attempt.

However, he did admit to being daunted by the scale of this latest challenge.

The 51-year-old father-of-two said: "The biggest worry is that the balloon could tear itself to pieces at the launch."

Inspiration hope

But he also said that he and 48-year-old aerial filming sequence co-ordinater Colin Prescot are ready to have a go for the record.

Colin Prescot said: "Why are we doing this? It's the excitement of making the first British manned mission into space. It's an unashamed adventure. And that's what we are, adventurers."

Andy Elson also said at the launch at Nelson's Column in London how he hoped his record-breaking attempt would be an inspiration to school leavers everywhere.

He said: "I'd like to say to all those kids about to leave school with no qualifications like me, you're not a write-off. There's still so much you can do."