Although offered protection from punishment by the FIA, Fernando Alonso may not be immune from repercussions by McLaren Mercedes as the Formula One spying scandal took another sensational twist yesterday.

Allegations emerged yesterday that Alonso had threatened to tell the FIA about the team’s possession of Ferrari secrets unless he was confirmed as their No 1 driver. The Spanish double world champion’s future with McLaren is in serious jeopardy.

It was revealed that Ron Dennis, the team prinicipal, and Alonso had a big row on the day of the Hungarian Grand Prix in early August, when Alonso argued that he should be treated as the lead driver ahead of Lewis Hamilton or be allowed to leave the team at the end of this season.

At some point in the exchange, Alonso is alleged to have told Dennis that he was prepared to reveal to the FIA, the sport’s governing body, that he had e-mails on his computer that showed that McLaren had been contaminated by secret technical information stolen from Ferrari.

Dennis decided, more or less on the spot, to inform the FIA, stealing Alonso’s thunder. Ironically, it was that which prompted the FIA to reopen its investigation into McLaren’s possession of Ferrari secrets.

This culminated on Thursday in a judgment in Paris by the World Motor Sport Council (WMSC), which fined McLaren a record £50 million for cheating and threw them out of this season’s constructors’ championship.

There was no official confirmation by McLaren sources of the exchange between Dennis and Alonso, who is under contract to McLaren until at least the end of next year on an annual salary believed to be about £15 million. However, it was widely known about yesterday in the paddock in Spa, where the Woking-based team and their ten rivals were preparing for tomorrow’s Belgian Grand Prix. Dennis, who arrived at the circuit at lunchtime, chose not to refer to the conversation explicitly in a statement that he issued last night. Nor did he comment on the intense speculation about Alonso’s future.

But, intriguingly, the four-paragraph statement did mention the day of the Hungarian Grand Prix on August 5, with Dennis confirming that it was then that he informed the FIA of the new and extremely damaging information held by Alonso. “I want to stress that once I became aware that new evidence might exist, I immediately phoned the FIA to keep them informed,” he said.

The revelations were seen by many observers as making Alonso’s position at McLaren untenable and the most vivid evidence yet that the Spaniard went through a phase this season when he was seriously rattled by Hamilton, who has led him in the drivers’ championship for months.

Perhaps significantly, the row with Dennis came immediately after the attempt by Alonso to stop Hamilton getting pole position during qualifying for the Hungarian Grand Prix by delaying in the pits to prevent the British driver completing his final flying lap. That obstruction by Alonso, which came in retaliation to Hamilton’s decision to ignore team orders, resulted in McLaren losing their constructors’ points for that race and Alonso being demoted five places on the grid.

Yesterday’s developments came as the sport was trying to come to terms with the scale of the punishment handed to McLaren. Although the headline figure of £50 million was widely publicised, it was being estimated that, once various additional conditions were taken into account, the team would have to pay only about £15 million to the FIA.

Away from the scandal and intrigue, the drivers went about their normal business yesterday, with two sessions of free practice at Spa. In the morning, Kimi Raikkonen was dominant for Ferrari, more than half a second quicker than Hamilton. Alonso was third, while Felipe Massa completed only two laps before crashing into a barrier.

In the afternoon, the McLarens were on top, with Alonso setting the fastest time of the day, just ahead of Hamilton. Afterwards, Hamilton insisted that, for him, driving for McLaren was a “great honour”, saying: “It’s been a traumatic year for everyone but we are all focused on winning.”

What the report said

— Mike Coughlan, the suspended McLaren chief designer, had more information than previously appreciated and was receiving information from Ferrari in a systematic manner over a period of months

— The information was disseminated to some degree within the McLaren team

— Pedro De La Rosa, the McLaren test driver, requested and received information from a source he knew to be illegitimate for use in testing in the simulator

— The secret information was shared with Fernando Alonso

— There was a clear intention on the part of a number of McLaren personnel to use some of the Ferrari confidential information in their own testing

— Coughlan’s role put him in a position in which his knowledge of Ferrari secrets influenced him in the performance of his duties