Nelson Piquet has sensationally told Formula 1 investigators that he was asked by Renault to deliberately crash at last year's Singapore Grand Prix. The son of triple world champion Nelson Piquet Snr. claims he met with technical head Pat Symonds and team boss Flavio Briatore hours before the sport's first night race. He then attended a second meeting with Symonds, the team's technical boss. The Brazilian claims it was agreed that he would crash to help teammate Fernando Alonso win the race. A hearing on September 21 is set to examine the allegations. Piquet claims he agreed to crash because he was under pressure and felt that his place in the team and his Grand Prix career were under threat. He says a particular part of the Singapore circuit was singled out because there were no cranes present to lift the car away, guaranteeing the use of a safety car. In the race Alonso pitted unexpectedly early and after Piquet's crash the double champion emerged as a strong contender for victory because the other drivers still had to stop for fuel. The Spaniard, who has denied all knowledge of the race fix, went on to score Renault's first victory of the season. Renault have refused to comment but Italian newspapers quote Briatore as refuting his driver's version of events, while Symonds said the meeting did take place but only as a conversation and not as a definitive plan of action. But investigators for Quest, the detective agency run by Lord Stevens, the former head of the Metropolitan Police, working with FIA stewards, claim to have uncovered further evidence. At the corner where the accident happened Piquet lifted his foot off the accelerator on every lap to prevent the car crashing as it lost grip on the kerbs. Every lap except the one he crashed on. Investigators are also probing Renault's claim that Piquet was the architect of the race fix and investigating why, far from being suspended after the race, he was re-signed, although he was ditched after half a season. There is further evidence that Piquet asked which lap he was on early in the race, although he was not due to pit for at least 10 laps more. Renault face expulsion from Formula 1 if the case is proven, and a fine stretching to tens of millions of pounds.