McLaren boss Martin Whitmarsh says his team will face a litmus test for its chances of beating Red Bull Racing to the world championship this year at the British Grand Prix.
With the Woking-based outfit due to introduce a major upgrade for Silverstone, which will include an exhaust-blown diffuser, the team has high hopes of an improvement in its form.
But with Red Bull Racing having taken a key victory on the streets of Valencia last weekend, Whitmarsh thinks the performance of his outfit at the British GP will show whether or not his team can take the fight to its main rival on high-speed venues.
Last year, Red Bull Racing dominated proceedings at Silverstone - with Sebastian Vettel and Mark Webber taking an easy 1-2 finish.
"It is an important race for us," Whitmarsh told AUTOSPORT about the British GP. "At a circuit like that we have to be competitive with Red Bull if we are going to be able to beat them this year. If we can be competitive there, we have a good chance to win both championships.
"It will be a big race, but it is not the end of it - whatever happens. If we beat them they will not stand still. If they beat us we are not going to stand still. I hope it will be close and certainly closer than last year."
Whitmarsh admitted that his team had been fairly downbeat about its chances for Valencia, with a number of McLaren's rivals having introducing upgrades for last weekend's event.
"We didn't know the scale of everyone else's upgrades coming here, but on Friday you could see a lot more in terms of upgrades, so to come out of this event with a second and third was fairly reasonable," said Whitmarsh.
"We should have been on the second row. In qualifying mode Red Bull were quicker than us, and both our guys made mistakes, but we were not about to beat the Red Bull.
"I think we had the slight edge on them in race pace, which we have had several times this season, and we thought there was going to be a bit more of a contest at the end. But unfortunately the penalty denied the opportunity."
He added: "To come out of here leading both world championships, we've seen what the others have got, and to have a decent upgrade, we must believe we are in the position to have a strong second half to the season and a world championship campaign."