On the eve of his second deadline, Max Mosley has written to the five teams - Brawn GP, BMW, McLaren, Renault and Toyota - whose entries for 2010 remain conditional, proposing an £86m budget cap in 2010 reducing to £39m in 2011.

Understanding the reluctance for teams and manufacturers to reveal their accounts, another facet of the budget row that threatens to destroy the sport, Mosley writes: "There will be self-reporting of compliance using a reputable auditor. Any suspicions of breach would be investigated by a mutually acceptable auditor of suitable standing."

Reminding the teams of tomorrow's deadline and urging them to make their entries unconditional, Mosley appears to give further ground.

"Subject to approval by the FIA's World Motor Sports Council, and by teams already having had their entries accepted, it is intended that certain amendments will be made to the 2010 Formula One sporting and technical regulations forthwith," writes Mosley, according to Reuters.

The five teams have until the close of business tomorrow in which to make their entries unconditional or face exclusion from the entry list. Ferrari, Red Bull and Toro Rosso, however, are already on the entry list even though they insist that they have no intention of participating.

The word in the paddock at Silverstone however, is that the teams still feel there is some way to go.