Richard Burns will miss the 2004 world championship after being diagnosed as having a brain tumour.

Burns withdrew from the Wales Rally GB after collapsing at the wheel of his Porsche earlier this month and was subsequently diagnosed as suffering from astrocytoma. He will undergo a course of radiotherapy to treat the condition.

"The doctors have advised that I am unable to get back in a rally car for the 2004 Championship and I have to accept that," Burns, 32, said. "I'm obviously extremely disappointed, but I am feeling very positive and I am determined to focus all of my efforts on getting back to full fitness as soon as I can."

Burns blacked out while travelling to Cardiff a fortnight ago for the Wales Rally GB. He was saved from a potentially fatal accident when his rally rival, Markko Martin of Estonia, took the wheel and steered the car to safety.

Burns was taken to hospital and ordered to miss the rally before undergoing further tests in London last week. Those tests revealed astrocytoma, a form of tumour that develops on the brain's glial cells.

Burns was due to rejoin Subaru, the team with whom he became the first English world champion in 2001, next season in a reported £5m deal.

"We are very concerned," said the Subaru team principal, David Lapworth, of Burns who did not win a rally in his two seasons at Peugeot. "There will always be future rallies and future championships, but for now Richard needs to put his own health first."

Subaru have to find a replacement for Burns to partner Norway's Petter Solberg, who won the drivers' title with victory in Wales. They could turn to Colin McRae, who is without a drive next year after losing out at Citroën. Nissan are expected to confirm today that McRae will contest the Paris-Dakar Rally for them in January.