Jenson ButtonWorld Champion Jenson Button is closing on a switch to McLaren-Mercedes in a deal that should be completed later this week.

The 29-year-old Briton is understood to have emerged as a McLaren target after negotiations to bring Kimi Raikkonen back to the team stalled over pay demands. A report in Britain's The Guardian newspaper on Tuesday said that following a visit to the team's Woking base last week, further negotiations have taken place.

Sources have confirmed that while no deal has yet been signed, Button is likely to commit to the team within the next few days. It is understood that the deal has not yet been agreed to by Button, although with little hope of remaining at the re-branded Mercedes Grand Prix team, it is unlikely that he would turn down the chance to join one of the most successful teams in the history of the sport.

Button had been negotiating a new Brawn deal since early in the season, with talks intensifying after he clinched the World Championship in the Brazilian Grand Prix on Oct. 18. But the team was unwilling to offer more than a $6.7 million-per-year deal – around half of what Button's management was asking. Despite Mercedes taking over the team, chief executive officer Nick Fry emphasized that nothing had changed in the Button discussions.

"I'm sorry to say, it's not going to change anything," Fry told the BBC. "We're running with a budget that is probably less than most of the others have spent and that's what Mercedes likes. In these financially constrained times, you do have to tighten your belt. We've had discussions with Jenson on what we think is a sensible salary, and this is not going to change anything in that respect."

Button would partner Lewis Hamilton on the team, with Mercedes considering running an all-German driver lineup. Mercedes Motorsport boss Norbert Haug admitted last weekend that Nick Heidfeld was a possible target, and the team is understood already to have signed Nico Rosberg.

Button's signing would appear to leave Raikkonen out of F1 for 2010, as the 2007 World Champion has made it clear that he considers McLaren to be his only option. It has been suggested that the Finn – who obtained a sizable financial settlement from his release by Ferrari – could take a year's sabbatical with a view to returning to F1 in 2011.