CARDIFF -- Welshman Richard Burns will undergo more medical tests next week after a mystery collapse that ruled him out of this weekend's World Rally Championship title showdown.

"What happened to him is something of huge importance from a health point of view," the former champion's Peugeot team boss told a news conference at British Rally headquarters on Thursday.

"Tests have been done on him on Monday and Tuesday which couldn't lead the doctors to find the reason for the symptoms that he had. Other tests will be made on him next week."

Burns, who is due to return to his former team Subaru for 2004, fainted while driving his Porsche on the motorway to Wales on Sunday with Estonian friend and rival Markko Martin as a passenger.

He was taken to hospital and told to rest at home for the remainder of the week after being released on Tuesday.

The Guardian newspaper reported that Burns, who had a crash in testing last month, also had a series of tests in a London hospital on Wednesday after a brain scan revealed no damage.

The Englishman had been fourth overall and five points off the lead as one of four drivers challenging for the title.

Amid speculation that Burns' situation could be an opportunity for out-of-work former champion Colin McRae if Subaru needed a replacement, Provera called for Burns to be allowed some privacy.

"We are sad for him, sad for us but mainly for him," he said. "Sad for the amount of stupid things we heard so far. A human being deserves privacy even though this human being is a public figure.

"When the time comes, it will be for Richard to tell what's happening to him. I only hope on behalf of Peugeot that what is happening to him can be solved."

McRae, who won the title with Subaru in 1995 and has now been dropped by Citroen, is looking for a drive but Subaru boss David Lapworth did not want to be drawn into the speculation.

"He's not a bad substitute, yes you're right," Lapworth told reporters. "But we're not thinking about that yet."

McRae, who shares the record of 25 wins with Spain's Carlos Sainz, has said he will not race next year and this weekend's rally could be his last championship appearance.

"For Richard it must be devastating," said Lapworth.

"He's got a great record on this rally and there's no question he could have won...we can only feel sorry for him and hope he's back in the car as soon as possible.

"I can only listen to what our doctors say and our doctors say there are so many explanations and possibilities that it's not even worth speculating about. We'll see what the tests show."