Two of Renault F1's major sponsors have decided to withdraw their support from the team ahead of schedule following the resolution of the 'race-fixing' scandal that saw team boss Flavio Briatore and director of engineering Pat Symonds forced out of Formula One.

Title sponsor ING and valued Spanish partner Mutua Madrilena both announced their decision on the eve of the Singapore Grand Prix, ironically the scene of the Nelson Piquet Jr crash in 2008 that sparked the situation. ING had been due to end its partnership with the team at the end of the season, as a result of the ongoing tricky financial climate, while Mutua Madrilena's involvement would have been called into question by Fernando Alonso's future plans, which link the Spaniard to Ferrari for 2010.

With Briatore and Symonds both voluntarily walking away from Renault F1 - before both being handed bans from the sport by the FIA World Motor Sport Council at Monday's hearing - the team was given a suspended sentence, with any future transgression leading to its own permanent ban, but will be on the grid in Singapore this weekend, with technical director Bob Bell likely to be at the helm.

"In light of the verdict of the World Motor Sport Council of 21 September 2009 concerning the events that occurred at the 2008 Singapore Grand Prix, ING will terminate the contract with Renault F1 with immediate effect," a company statement confirmed, "ING is deeply disappointed at this turn of events, especially in the context of an otherwise successful sponsorship."

The Dutch-based company is thought to have provided over 50 per cent of the team's total sponsorship, around $54m a year, and its withdrawal is likely to leave the team in a delicate financial situation. No replacement had been announced for 2010, and the marque's participation in the sport could again be thrown into doubt should funding to prolong the programme not be found.

Mutua Madrilena's decision, announced earlier on Thursday, will only add to the pressure on the Enstone team to shore up its sponsorship for next season. The company is thought to have contributed around $7m a season to the cause.

"Mutua Madrilena believes the conduct of the relevant people in the team was of extraordinary seriousness and not only compromised the integrity of the sport but also put the physical safety of spectators, drivers and circuit personnel at risk," the insurance giant said of the incident which saw Piquet Jr ordered to crash out of the inaugural Singapore event in order to allow team-mate Alonso to benefit from the ensuing safety car period, "This could affect the image, reputation and good name of the team's sponsors."

The Spanish company has said, however, that its decision to quit Renault would not effect its relationship with Alonso, who insists that he knew nothing of the plot - which ultimately allowed him to win the grand prix.