The return of one M Schumacher to Formula One this year has got me thinking. How quick will he be, and is his best still good enough? While failing to sleep the other night, I may have inadvertently devised a way to work it out.

It’s all thanks to his team-mate Rubens Barrichello, who drove the same car as Michael in 2005 at Ferrari, and also drove the Brawn/Mercedes Silver Arrow that Michael will inherit in 2010, albeit revised and updated for next year.

2005 was the last season that Michael and Rubens raced together in the same machinery. Using race results from the 2005 season as a basis – specifically those races where both Ferraris finished, and adding a notional 45 seconds for results in which Rubens finished a lap behind Michael – you can work out that, over a race distance, the German was on average 23.8 seconds quicker than the Brazilian.