Could a Formula One race be held around London's streets?
F1 supremo Bernie Ecclestone, unhappy with Silverstone as a venue for the British Grand Prix, has refused to rule out switching the race to the capital.
On the face of it, it seems a crazy idea. The average speed of traffic in central London is three miles an hour - hardly the basis for a thrilling battle between the finest drivers on the planet.
But think about the notion a little more, and it suddenly starts to seem possible - in theory at least.
How Schumi and co might race round the streets of London...
Let's put on hold the very real possibility that this is merely Ecclestone continuing to put the squeeze on the British Racing Drivers' Club, which owns the track at Silverstone.
If you can stage a Grand Prix around the narrow streets of Monte Carlo, why not London?
26 miles of London's roads are closed every Sunday in April for the marathon. On the basis that each lap of the Monaco GP is only 2.09 miles long, a London GP would require a far smaller area to be cordoned off than the marathon.
In terms of the route, the race would require a combination of long fast straights, tight technical turns and a stream of famous landmarks to underline its unique status.
THE UNANSWERED QUESTIONS
Would Bernie swap his helicopter for the Tube?
Would drivers be fined for using the bus lane?
Would drivers have to pay the congestion charge?
Could any of the cars beat an illegal mini-cab off the lights?
What better place for the starting-grid than the Trafalgar Square end of the Mall, with the cars screaming down towards Buckingham Palace in the first few moments of the race?
Diving right at the Queen's official residence (would Elizabeth swap Corgis for cornering for the afternoon?) the route would follow Constitution Hill to Hyde Park Corner, see the cars go left around the roundabout and then up Park Lane - within a stone's throw of motor-racing legend Stirling Moss' Mayfair home.
At Marble Arch the cars would have to follow the existing flow round to the left, in a turn as tight as the Loews Turn at Monaco, before diving into top gear for the long straight down past the department stores of Bond Street to Oxford Circus.
Barrelling down Regent's Street, the route would ease round the statue of Eros in the centre of Piccadilly Circus and then chase up Shaftesbury Avenue to Cambridge Circus.
A tight right-hander takes the drivers down Charing Cross Road, past Leicester Square and back into Trafalgar Square, where they sizzle round Nelson's Column before exiting through Admiralty Arch and back into the Mall.
Sure, there would be issues with narrow roads and a bumpy surface - but those are exactly the factors that make Monaco such a special test of drivers' skills.
Where would the teams set up their garages? The smart answer is King's Cross, seeing that the area has been the pits for years already.
But in terms of our starting-grid, you would have to go for Horse Guards Parade or St James' Park.
So that's that - a piece of cake, if you ignore the enormous issues of the fantastical cost, the serious safety concerns and the horrendous problems of seating and transporting hundreds of thousands of spectators...