PAUL Di Resta suffered a bitter blow last night when he was ordered to start this afternoon's British Grand Prix at Silverstone from the back of the grid.

The Force India driver had earlier achieved the best qualifying result of his Formula One career, setting the fifth-fastest time of the day with a lap of 1min 30.736secs.

But post-qualifying testing showed the car to be underweight at 1.5kg below the minimum requirement of 642kg.

FIA technical delegate Jo Bauer discovered the discrepancy and immediately referred the matter to the stewards.

The weight of the car and its driver count together and Force India said later that the problem lay with Di Resta rather than the vehicle.

They said the car was weighed after final practice and again after qualifying, producing identical results.

It was then discovered that Di Resta was mysteriously 1.5kgs lighter after qualifying as opposed to final practice. Force India director Bob Fernley said that when the Scot was weighed again later he was back to his normal weight.

The team considered racing under appeal, but the Silverstone-based marque eventually decided to accept the stewards' decision.

Di Resta, 27, from Bathgate, had said immediately after qualifying: "We've known all season that we have good, raw pace in both qualifying and race trim and we showed that again today.

"After Monaco and Canada, where qualifying didn't go exactly as we'd planned, today everything went perfectly and I have to give the guys in the garage and on the pitwall a big thanks.

"Silverstone's a track I've always loved and it's a circuit which I believe suits our car. I think we showed that again today too. This track takes a lot of commitment and you need to build up your speed but I think we saved our best till last — and that's when it mattered."