Lewis Hamilton should not be written off as a world championship contender despite errors that have seen him fail to score in successive races, says the new title leader Felipe Massa.

The Ferrari driver won the French Grand Prix at Magny-Cours to become the first Brazilian since Ayrton Senna in 1993 to lead the Formula One standings.

Hamilton, meanwhile, finished 10th but the British driver insisted that at his home Grand Prix at Silverstone on 6 July he will hit back from his pit-lane howler in Canada and a penalty imposed in France for cutting a chicane.

Massa took full notice of that warning and said: "Lewis is still a threat. It's only the middle of the championship with a long way to go.

"Remember, I didn't score in the first two races and I'm leading the points table. My team-mate Kimi Raikkonen didn't score in the two races before France and he's completely fighting for the championship. So we cannot take anybody away from the fight."

The reality confronting Hamilton, however, is that after a sensational debut season he is now losing vital ground by making too many elementary mistakes.

Following a stunning victory in Monte Carlo last month the 23-year-old McLaren driver remains stuck on 38 points, 10 behind Massa and also trailing Robert Kubica and Raikkonen.

And Hamilton's professionalism has come under fresh attack from Sebastian Vettel, the Toro Rosso driver who was cut up in the frantic opening stages yesterday as Hamilton sought to make up for his 13th place on the starting grid - he was punished with a 10-place penalty for ramming Raikkonen's stationary car in the pit lane in Canada.

Hamilton's move on Vettel triggered a stewards' investigation and subsequent drive-through penalty that ruined his hopes of salvaging at least a couple of points from his lowly starting position, but the German had no sympathy for his rival. Vettel said: "He cut the chicane completely. I had a similar situation at the Monaco chicane, when I was too late on the brakes. I overtook two cars but I let them go again and so the issue was settled.

"If someone stays out in front, there is a penalty. I think he should have let me past again because he had a better car and could have passed me again."

Hamilton remained defiant. Recalling the incident with Vettel he maintained: "I drove what I thought was a fair race. I went into the corner and I believe I was ahead on the outside. I couldn't turn in on the guy otherwise we would have crashed so I took the outside line, lost the back on the marbles and went over the kerb.

"I continued because I don't believe I overtook him by going over the kerb, I actually took him before that."

Hamilton and his McLaren bosses were today holding a special meeting in a bid to regroup ahead of the British Grand Prix. It is clear they are beginning to embrace a siege mentality over criticism of his driving and the FIA's apparent intent to keep hounding the team following last season's spygate scandal.

Hamilton said: "I'll push with the team, focus on the next race and hit 'em hard. I am absolutely 100 per cent aiming to bounce back at Silverstone."

Raikkonen's hopes of victory were wrecked by a broken exhaust suffered halfway through the race when he was leading.

However, the Ferrari driver said: "This sort of thing can happen in racing, and I have to look on the bright side because luckily I had built up quite a good lead in the first part of the race and I still took eight points."