It has emerged that whilst it had previously been thought that only Flavio Briatore, Pat Symonds and Nelsinho Piquet had been in on the explosive 'Singapore-gate' cheating scandal that has rocked Formula 1 in recent weeks, a fourth Renault F1 team member also knew of the conspiracy - and it was the so-called Witness X's damning testimony, it is understood, that sealed Briatore's fate and indefinite ban from the sport.

Witness X has been described as a 'whistleblower' who, 'although not a conspirator himself, knew of the conspiracy at the time of the 2008 Singapore Grand Prix'. It has been revealed by the FIA that Witness X gave evidence to the governing body against disgraced former Renault F1 managing director Briatore - who has been banned from having any future involvement in motorsport for an unlimited period, including driver management - and erstwhile executive director of engineering Symonds, who has for his part been banned for five years.

Renault F1 was found guilty by the World Motor Sport Council (WMSC) on Monday (21 September) of having manipulated the result of the top flight's inaugural night race after Briatore and Symonds instructed Piquet to deliberately crash out in order to prompt a safety car period that enabled team-mate Fernando Alonso - who the FIA has confirmed was unaware of the plot - to triumph from a disadvantaged grid position following an engine failure in qualifying.

The French manufacturer received a two-year suspended ban from F1 for the crime of race-fixing, whilst the eleventh-hour evidence convinced the FIA that Briatore was 'personally and directly involved in the planning of the conspiracy'.

The flamboyant Italian has disclosed that he is 'distraught' at the outcome of the latest controversy to afflict F1, and is threatening legal action against the governing body for loss of reputation as he continues to protest his innocence [see separate story - click here] - as it has been revealed that he could also be removed from his post as co-owner, chairman and board director at London football club Queens Park Rangers (QPR).

'Renault F1 stated in its submissions of 17 September 2009 that Witness X had confirmed that Mr. Briatore had known of the deliberate crash plan before it had been put into effect,' read an official FIA statement. 'With Renault's co-operation, Witness X was subjected to detailed interview and examination.

'Renault F1 has concluded that the following had knowledge of the conspiracy to cause a safety car: Nelson Piquet Junior, Pat Symonds, Flavio Briatore and [Witness X]. [Witness X] was told of the idea suggested by Nelson Piquet Junior by Mr. Symonds, whilst in the presence of Mr. Briatore.

'[Witness X] objected to the idea and sought to distance himself from it. He did not know the plan was to be carried into effect until the crash happened. As a result of the evidence, including Mr. Piquet's admission, Mr. Symonds' responses and [Witness X's] evidence, Renault F1 concluded that they and Mr. Briatore must have known about the conspiracy.

'When the FIA's advisors interviewed Witness X, he expressly confirmed that Mr. Briatore was involved in the conspiracy because Witness X had been personally present at a meeting shortly after qualifying on Saturday 27 September 2008 when Mr. Symonds had mentioned the possibility of a crash plan to Mr. Briatore.'

Witness X's identity - unveiled by Renault shortly before the WMSC hearing - is known only to FIA President Max Mosley and a handful of legal advisors. The FIA added that it was confident nobody else at the Enstone-based outfit had been privy to the 'secret conspiracy' - quite possibly safeguarding Renault's ongoing participation at the highest level and outwardly lenient penalty.

"Renault made it easy for the FIA," mused former team owner Eddie Jordan, speaking to the BBC. "They came clean and got rid of the people involved. We don't know the full evidence that has been brought before the hearing, but it's somehow proved that only certain people were involved."