Two people have died and three have suffered life-threatening injuries in a crash between a minibus and a lorry.
The crash happened at about 12:20 BST on the eastbound carriageway of the M4 between junction 14 at Hungerford and junction 13 at Newbury.
Two people in the minibus died at the scene and six other people, including the bus driver, were injured.
The eastbound carriageway reopened at about 21:30 after being closed for investigation work.
Thames Valley Police have appealed for anyone who saw what happened or has dashcam footage to contact the force.
South Central Ambulance Service said three people in the minibus had been taken to hospitals in Oxford and Bristol with life-threatening injuries.
Three other people in the minibus suffered less serious injuries and were taken to hospitals in Swindon and Reading.
Two of the three people seriously injured were flown to major trauma centres at the John Radcliffe Hospital in Oxford and Bristol Southmead Hospital.
The third was taken by road, also to the John Radcliffe.
The driver of the HGV was also taken to hospital having received minor injuries.
The westbound carriageway was closed to allow three air ambulances to land but has since reopened.
Thames Valley Police earlier advised motorists to avoid the area if possible.
James Lloyd, who passed the scene shortly after the crash, said a large articulated lorry had gone into the back of a minibus.
The force of the impact had shunted the minibus about 100 yards along the carriageway, he added.
Dominique Hamblin tweeted: “I have never seen an accident site so horrendous looking and with such an enormous emergency services response as on the M4. Looked nasty, I pray it’s not that bad.”
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