Mercedes boss Ross Brawn has revealed his frustration with the performance of his team's car after a poor points haul at the British Grand Prix.
Michael Schumacher's seventh place at Silverstone meant Mercedes only picked up six points for their weekend's work as they failed to build on Schumacher's podium finish in the previous race in Valencia.
Brawn said: "Our performance has been up and down recently, ranging from podiums to lower points finishes.
"We need to work hard to improve our level of consistency and ability to challenge at the front."
Despite their inconsistencies, Merecedes did win the third race of the season when Nico Rosberg won the Chinese Grand Prix.
