The M4 has been closed between junctions one and three after cracks were discovered in a viaduct. It is expected to remain closed until Thursday.
With fears over how London will cope during the Olympics hitting the news on a near-daily basis, a forced closure of one of the main routes into London from Heathrow must be near the top of LOCOG's worst case scenario list.
The M4 closure is the latest in west London's road woes — the Hammersmith flyover was partially closed in December, only fully re-opening five months later (for the reasons why, read this excellent technical explanation).
The Highways Agency has said it expects all work to be finished before the start of the Games. A diversion is in place on the adjacent A312 and the A4, though drivers are advised to allow extra time for their journeys.
Photo by Phil4 in the Londonist Flickr pool.