THE British probe that will search for life on Mars began the final leg of its journey yesterday after separating from its mother ship.

At 8.31am, an explosive bolt was fired to send the Beagle 2 lander spinning away from the Mars Express spacecraft to which it has been fixed since its launch on June 2, bound for touchdown on the Martian surface early on Christmas Day.

Scientists and engineers had to endure a two-hour wait before data confirming the successful separation could be returned to the European Space Agency's control centre in Darmstadt, Germany. Had the procedure failed, the 69kg (152lb) Beagle 2 would not have been able to land, and its mother ship's mission would also have been jeopardised.

At 10.41am Rudi Schmidt, the Mars Express project manager, said that early data meant that he could be 95 per cent confident that separation had been successful, raising the hopes of more than 200 team members and supporters watching a live satellite link at the Royal Geographical Society in London.

At 11.11am the gathering burst into applause and cheers as Mike McKay, the flight director, announced: "We can confirm we have Beagle 2 separation." Pictures showing the lander drifting away from Mars Express arrived at 2pm.

David Southwood, the agency's director of science, said: "It's been a very tense morning, but I'm fully confident that mother and baby are both doing really well, and I'm looking forward to seeing how the family develops."

Everett Gibson, of Nasa, which will land two rovers of its own on Mars next month, sent a message of support: "The Mars team has asked me to say, 'Great job. We wish you the best of success and we look forward to meeting you on Mars.' " Colin Pillinger, Professor of Planetary Sciences at the Open University and the main architect of Beagle 2, said that Beagle 2 had no propulsion system of its own, and was "in the hands of Mr Newton" as it descended towards Mars. Mars Express played the part of "a champion darts player aiming at a bull's-eye", throwing Beagle 2 on to the precise trajectory that should bring it down to the Isidis Planitia landing site at 2.54am on Christmas Day, he said.

Mars Express has until now also been on a collision course with Mars and it will today fire rockets to steer itself away from the planet and into orbit. It should also reach its goal on Christmas Day.

Had Beagle 2 refused to separate, the 69kg of extra weight that Mars Express would have had to carry would have prevented it from reaching the optimum orbit for its scientific experiments. These include mapping the Martian surface in high resolution, analysing the planet's geology and atmosphere and using X-rays to look a mile underground.

Beagle 2 still has 2 million miles of its 250-million mile journey to go, and should reach the top of the Martian atmosphere at 2.47am on Christmas Day.

Professor Pillinger will not say exactly how much the mission has cost, but the total is estimated at between Pounds 40 million and Pounds 45 million. British space experts are unanimous that, while Beagle 2 has been a team effort, it would never have happened without his drive and obstinacy.

As the probe slows from 25,500mph to 12,500mph, the scientists hope that a heat shield will protect it from the temperatures of entry. A pilot parachute will be deployed at 2.50am, pulling out the main parachute a minute later. This will slow its descent to 40mph, and it will be protected from the final impact, at 2.54am, by three gas-filled bags. It will bounce several times before coming to a halt.

The bags will deflate, and Beagle 2 will unfold its petal-like solar panels.

Professor Pillinger's team hopes to receive its first signals at about 6.30am. It will not be able to transmit before then, as the team must wait for Nasa's Mars Odyssey spacecraft to arrive overhead and relay Beagle 2's signals to Earth.

The lander's main payload is its "paw", which will analyse the Martian rocks and atmosphere for chemical signatures that could indicate life.

* Ancient Greeks called Mars Pyroeis (Fiery Star). After they immersed themselves in Babylonian astrology, Mars became Ares, after the Greek god of war.

* Now it is named after the Roman god of war.

* The "blood-red" surface is rust (oxidised iron-rich minerals).

* At 14 miles high and 341 miles across, the Mars volcano Olympus Mons is the solar system's largest.

* In about 350BC the Greek philosopher Plato included a description of Mars in his dialogue The Timaeus.

* The influence of the name Mars is seen in many European names such as Mark, Martin, Marcia, Mario and Marcel.

* In 1609 Johannes Kepler calculated Mars's orbit, which led to his laws of planetary motion.

* Mars has inspired more than 100 films