Button wants Hamilton challenge - Ross Brawn

Ross Brawn has admitted disappointment with Jenson Button's decision to switch to Mercedes, but insists the move has nothing to do with money.

Button, the 2009 world champion after sticking with the Brawn team in the wake of Honda's withdrawal, will be Lewis Hamilton's McLaren teammate next year.

The 29-year-old Briton's Brawn/Mercedes talks were rumoured to have failed due to disagreements about his 2010 salary.

"His decision is disappointing because we worked so well together," team boss Ross Brawn told Germany's Auto Motor und Sport.

"But whatever is said, it was not about the money. In the end our offer was even more attractive than McLaren's.

"But it doesn't make sense to employ a driver who would not be happy and sees a bigger challenge somewhere else. Further negotiations would have been pointless.

"Jenson obviously wanted to be in the same car against Lewis Hamilton.

"That's brave and I have to respect it," added Brawn.