Mr Bush performed a tandem jump on his 75th birthday

Mr Bush and his wife will immediately return to Houston for a birthday party.

"Given the charitable nature of these events, we believe President Reagan would be the first to say, 'the show must go on,'" the organisers said.

Reagan died in Los Angeles on Saturday at the age of 93 after a 10-year battle with Alzheimer's disease.

Mr Bush served as Reagan's vice-president, before going on to take the White House himself, becoming America's 41st president.

Veteran leaper

A practice session for the jump which was originally scheduled for Friday, has been moved forward to Thursday so as not to clash with the funeral.

Jumping out of planes is becoming something of a habit for Mr Bush: in World War II, as a navy pilot, he was forced to bail out of a damaged plane; and five years ago he marked his 75th birthday with a tandem parachute jump.

On Sunday he will jumping solo, but will be surrounded by members of the Golden Knights, the US army parachute team.

"This is a very, very important thing to the president. This is a solo jump. There will be knights around him, but it is not a tandem jump," organiser Jim McGrath said.

About 5,000 people are expected to attend the parachute jump over the Bush library at College Station and a similar number will turn out for the gala party the day before.