“Jenson is obviously a great driver and for those teams without their full complement of drivers, he's got to be a target,” Brawn told BBC radio.

Button took a hefty pay cut, reported at around US$8.33 million, before the start of the season to drive for Brawn.

The 29-year-old was rewarded for his loyalty with a title that would have seemed impossible a year ago but he now wants to have his salary restored to a level more appropriate for a champion.