Formula One's governing body has offered Renault's second-in-command immunity from punishment in exchange for full disclosure about "crashgate," a report said Tuesday.

Pat Symonds, director of engineering at Renault, has been told that if he comes clean over how and why Nelson Piquet junior drove his car into the barriers in Singapore in 2008, he will escape sanctions.

The sanctions could include a life ban from the sport, according to the report in London-based The Times newspaper, which cites unnamed sources.

Former driver Piquet and his father, three-time world champion Nelson Piquet senior, have claimed that the Renault team conspired to fix the outcome of the Singapore Grand Prix, in a blow to the sport's reputation.

The offer of immunity from the International Motorsport Federation (FIA) comes after its stewards investigating the claims interviewed Symonds at the Belgian Grand Prix late last month.

Symonds initially stonewalled when questioned in detail by FIA stewards about claims that he not only asked Piquet to crash in the Singapore race but went through with him where the accident should happen, according to the paper.

After refusing to answer a series of key questions, Symonds remarked at one point: "I have no intention of lying to you. I have not lied to you, but I have reserved my position just a little."

Renault have been summoned to appear before the FIA's International Motor Sport Council in Paris on September 21 to answer the allegations that Piquet was asked to crash his car deliberately into a wall during the race and so facilitate a victory for team-mate Fernando Alonso.

Renault in response have accused Piquet of blackmail and announced they were launching criminal proceedings against him and his father.

Renault F1 boss Flavio Briatore has denied all the accusations against him -- notably conspiring with team management and Piquet to cause a deliberate accident -- saying they were "outrageous lies".