Hamilton's frustration not hampering Mercedes' F1 morale - Brawn

Hamilton has refused to sugar-coat his feelings over his 2013 form and continued tyre issues.

After falling back from pole to fifth place in the German Grand Prix last weekend, Hamilton suggested victory was currently out of reach, despite team-mate Nico Rosberg's British GP win a week earlier.

"It would be good to get a win at some stage, but at the moment it really doesn't feel like it's going to happen on my side," said Hamilton.

But asked if such comments were affecting Mercedes, Brawn insisted Hamilton's outspoken interviews did not reflect his "constructive" approach to helping the team resolve its problems.

"Lewis wears his heart on his sleeve, but he was very constructive after the race," said Brawn.

"They are healthy frustrations, not negative, and both drivers gave us a good insight into what is going on in the debrief."

Brawn said his own feelings on Mercedes' form were moderated by memories of how much the team had struggled prior to 2013.

"We have to look at where we came from," he said.

"We are disappointed because in Germany we scored 12 points. In the second half of last year we would have given our right arm for 12 points.

"We are still second in the championship and we have a lot of things we can do."