Formula One world champion Jenson Button visited McLaren, fuelling speculation he could be lining up a switch from Brawn to become Lewis Hamilton's team mate next season.

"Having just landed at Heathrow (airport), Jenson made a small detour to Woking to say a quick hello," a McLaren spokesman said.

He confirmed the 29-year-old Briton, who was given a guided tour of the factory, met McLaren team principal Martin Whitmarsh.

Button is out of contract with Mercedes-powered champions Brawn, who are keen to retain him but not at any price.

Team boss Ross Brawn said earlier this week the chances of a deal being done were 99 percent, hinting also the team might give the driver more scope to benefit from personal sponsorship.

"We can offer a higher proportion of driver freedom and that will probably be the route we will go," he said.

Button took a significant pay cut, around 5 million pounds ($8.37 million) according to some media reports, to stay with Brawn this year after their predecessors Honda pulled out last December.

Although driver salaries are coming down as teams cut costs, Button wants his pay restored to something more appropriate to a world champion -- likely to be in the region of 8 million pounds.

McLaren, with 2008 world champion Hamilton earning considerably more than that, would have no problem meeting Button's financial demands.

If Button were to join, McLaren would then have a line-up of champions for the first time since the late Brazilian Ayrton Senna and France's Alain Prost were at the team in 1989 as well as an all-English pairing.

The Guardian website (www.guardian.co.uk) said Button and his manager Richard Goddard were given an escorted tour of McLaren's facilities.

"As I've said many times before, Jenson wants to drive a car which is capable of winning the next world championship," Goddard told the newspaper.

"We've been talking about possible terms for 2010 with Brawn for months and we're not being difficult or unreasonably expensive in our demands for Jenson.

"In fact, we've given up quite a lot of negotiating ground in our discussions with them."

The paper said a contract could be signed next week.

McLaren's former driver Kimi Raikkonen, who has left Ferrari, would be the Woking team's fallback if the Button deal failed. Germany's Nick Heidfeld was third in line.

"I think it's also important that Jenson wants to feel valued in whatever situation he finds himself next season," said Goddard.

"He needs to explore all the feasible options."