TRAFFIC is building back to Newbury following an accident on the M4 this afternoon.
Thames Valley Police said that two cars were involved in a collision on the eastbound carriageway between junction 13 (Chieveley) and junction 12 (Theale) at 4.39pm.
Ambulance and fire crews are on the scene.
Highways England said that two lanes are closed with delays of 50 minutes eastbound, with delays of 30 minutes westbound.
Newbury resident Chris Hall Tweeted: "Avoid travelling northbound through Newbury onto A339 up to Junction 13 M4. Due to accident on M4, its a complete car park."
Normal conditions are expected from 8.30pm.