Lewis Hamilton’s prospects of becoming the first driver to finish as Formula One world champion in his rookie season were under threat last night after a leading member of his team was accused of involvement in espionage against Ferrari.

In a day of sensational revelations that rocked the sport, the Surrey home of Mike Coughlan, 48, the McLaren Mercedes chief designer, was searched by police after a tip-off from Ferrari about the alleged theft of a large amount of technical information from their factory in Maranello, Italy.

Ferrari are linking the information allegedly found in Coughlan’s possession with their investigation into Nigel Stepney, a British-born senior mechanic, who Ferrari claim has been involved in the unauthorised leaking of information and an alleged attempt to sabotage their racing cars.

Stepney, who has denied the allegations and claims that he is the victim of a Ferrari “dirty tricks” campaign, was dismissed early yesterday. His lawyer has said that, when he returns from holiday this week, he will hold a press conference in Italy at which he will demonstrate his innocence.

McLaren would not confirm Coughlan’s identity, but issued a statement in which they said that they had become aware yesterday that a “senior member of [our] technical organisation” had received a package of technical information from Ferrari at the end of April.

The affair has the potential to cast a long shadow over Hamilton’s glorious debut season. Depending on the outcome of the investigations in Italy and Britain, legal challenges could determine the winners of the drivers’ and manufacturers’ championships. A spokesman for the FIA, the sport’s governing body, said last night: “We have received information on this matter, which we are examining.”

The scandal comes as Hamilton, who has finished each of his first eight races on the podium and won two grands prix in a record-breaking start to his Formula One career, prepares to drive in front of thousands of British fans at Silverstone next weekend.

At the heart of the case is highly secret technical information about car performance that results from millions of pounds’ worth of research. Ferrari believe that the improvement in McLaren’s performance after the Spanish Grand Prix on May 13 is consistent with the apparent leaks at the end of April.

In the first four races of the season, Ferrari held a decisive advantage over McLaren, but this was overturned in the subsequent races in Monaco, Montreal and Indianapolis. Last weekend, in the French Grand Prix at Magny-Cours, Ferrari were back on top, scoring a one-two via Kimi Raikkonen and Felipe Massa.