Lewis Hamilton: "It's been a productive day. We got through our run-plans well, and my long-run pace is better than it was at Silverstone, which is a good thing.

"We've got some updates on the car and they seem to be working, which is also positive. But it's only Friday, so it's too soon to draw conclusions - and, besides, and we don't know what programmes the other teams were running.

"The Ferraris look like they're up there, and the Red Bulls seem quick too, but anything can happen in the race and we'll be working hard tonight and tomorrow to maximise our chances."

Jenson Button: "It's been a slightly frustrating day for me. I couldn't get a good balance on the car this morning - and, once we'd found some rear grip in the afternoon session, my KERS Hybrid system was no longer working. That cost me quite a bit of lap-time under braking and on corner exits.

"Then, with 20 minutes of the afternoon session remaining, a problem with an experimental exhaust brought my day to a premature end. It was a test part and failures sometimes happen when you're trying new things on a Friday.

"Looking to tomorrow, I think it will be difficult for us to beat the Red Bulls in qualifying. But our aim is to race with the front-runners on Sunday afternoon."

Martin Whitmarsh, Team Principal: "Jenson had a KERS Hybrid problem today, and consequently had to do a bit of running without the lap-time benefits that KERS Hybrid confers.

"The experimental exhausts that he was testing also failed, which cut short his track time - but that's an inevitable result of our having to use Fridays for testing.

"Lewis had a more trouble-free day and completed a competitive long run, which was encouraging. But today was basically a data-gathering exercise, and we'll now analyse that data overnight in preparation for qualifying tomorrow."

To check out our Nurburgring practice gallery, click here