Police have issued another appeal for information today as a motorcyclist remains in serious condition after Monday's M4 accident.
The man, believed to be from the Maidenhead area, is suffering from head injuries. He was airlifted to John Radcliffe Hospital in Oxford after the accident which happened at about 8.30am.
Officers want to speak to anyone who witnessed the collision, which happened eastbound, just before junction 7.
It involved a motorbike and three cars.
The carriageway was closed for a number of hours. The westbound carriageway was also closed for a short period for the air ambulance to land.
Anyone who witnessed the collision should phone police on 101 or phone Crimestoppers anonymously on 0800 555111.
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