Mike Kendrick: Richard said "brilliant, brilliant, brilliant!"

The flight control centre in London said the crew were unable to comply with the Chinese order to land made on Tuesday morning because it would be too dangerous.

Project Manager Mike Kendrick said: "Perhaps now they can start to enjoy this flight. We are so pleased.

"It was a showstopper. I have spoken to Richard and he is absolutely delighted. 'Brilliant, brilliant, brilliant,' is what he said."

At an earlier press conference he said the idea of the balloon coming down in its present position was "horrific - I'm not even going to contemplate it".

The flight is presently over the mountainous Tibetan plateau - some of the coldest and most inhospitable terrain in the world - and about 10 miles inside China.

He said that the crew had been asked to land at a small airport 50 miles north of the Chinese border with Bhutan, but they could not comply because they could not steer the balloon and there was a danger of it icing.

"Ice can collect on the balloon in seconds and tons of it. If you get into that icing situation, you're on the ground and in a very serious situation," he said.

BBC Correspondent Daniela Relph reports from the project control centre

Mr Kendrick said the balloon was already freezing badly and ice on its satellite telephone antennae was making communication difficult, although the crew could still be reached by email.

Piloted by Branson, American Steve Fossett and Sweden's Per Linstrand, the balloon crossed from Nepal into Chinese-ruled Tibet just before 2200 GMT on Monday.

The BBC's Carrie Gracie: "No accidental shooting down of the balloon"

The balloon is presently north of an approved "corridor" over China - which runs south of the 26th parallel - and had been violating restricted airspace.

It crossed the Himalayas further north than planned due to diversions around violent Mediterranean storms and air strikes on Iraq.

On Tuesday, China warned it would not take responsibility for the consequences if the balloon continued on its present course.

BBC Correspondent Geeta Guru-Murthy: The Balloon crossed into Chinese airspace 250 miles off-course

British diplomats in Beijing have been conducting intense negotiations with the Chinese side to try to allow the balloon to continue its mission.

Personal record

On Sunday, Mr Branson and Mr Lindstrand broke their personal duration record of 48 hours set during their record-breaking 1991 crossing of the Pacific in a hot air balloon.

Now the flight has been allowed to progress, it present track will take the balloon straight over England, meaning Mr Branson could fulfil his dream of landing in his Oxfordshire garden.

It is also due to fly over San Francisco on Christmas Day before completing the round-the-world journey on New Year's Eve or New Year's Day.