What is 'Plan B' if M4 stays shut?

The Olympic family arrives on Monday - that is most of the athletes, International Olympic Committee (IOC) delegates and officials.

Yet the main route into town from Heathrow, the M4, is out of action.

The Highways Agency had hoped it would be opened by Thursday rush hour, but late on Wednesday it emerged that wouldn't be the case.

All the Highways Agency can say now is it will open in the "next few days" and that "due to the complexity of the operation, more time than originally envisaged is required to complete the work safely".

That's bad news for commuters who are seeing journey times increase by up to an hour. And it could be awful news for the Olympics and London 2012.

If it's not open by Monday then the key M4 Games Lane (the reactivated M4 bus lane) can't be used.

That means IOC delegates, athletes, officials and the international media will get stuck in the traffic around the M4 as they try and get to central London on other routes.

You can only imagine the reaction to that. The roads minister has admitted it would be "hugely embarrassing".

'Race is on'

The question is: are there any 'Plan Bs' to get the Olympics family to the Games without suffering with congestion.

Let me know your thoughts - because the race is on.

Not the 100m - this is about the race to re-open the M4 before the Olympics arrives.

Update: I've spoken to Transport for London which has confirmed it is looking at alternative routes into London.

Among the options are Heathrow Express, A40, A4 and A30.

A spokeswoman told me that if it was necessary they are confident they can manage it and get athletes and competitors to places they need to be.