Bernie Ecclestone has hit back at those scoffing at his apparent plans to front a London street race.
Insiders have dismissed the stories either as clever publicity, or a masterly diversion from the Gerhard Gribkowsky corruption scandal.
But, according to the Guardian, he told business journalist Christian Sylt this week: "We are getting on with it.
"It is no joke, 100 per cent completely no joke."
A separate report in Germany's Kolner Express linked the appearance at Silverstone of Olympic Games chief Jacques Rogge with reports F1 could use London's Olympic stadium as the scene of a grand prix.
"A London grand prix would be bigger than the Olympic Games," Ecclestone is quoted as saying.
In other F1 circuit news, Luca di Montezemolo has admitted he would like Ferrari's Mugello track to host a grand prix.
The flowing circuit near Florence, renovated last year and used for a F1 test earlier this season, is gearing up this week to host MotoGP.
"It would be a dream come true to one day also see a formula one world championship race take place at Mugello," Ferrari president Montezemolo said.
Read more: Ecclestone insists London GP plans 'no joke'