The M4 motorway is closed in both directions between J13 (Newbury/Chieveley) and J14 (Hungerford) following a serious collision.
Emergency services, including the Air Ambulance, are on scene, with National Highways Traffic Officers assisting. The incident was first reported shortly before 1pm today (12 August).
Westbound traffic is also blocked, with delays building on approach. Motorists are being advised to allow extra travel time and to follow official diversion routes.
Diversion information is available via National Highways travel alerts.
Meanwhile, on the M25 clockwise, three lanes remain closed between J16 (M40) and J17 (Rickmansworth) after a separate collision. Congestion is currently around six miles, adding at least 30 minutes to journey times.