The Olympic gold medal-winning sprinter Linford Christie was driving on the wrong side when he collided head on with a taxi carrying a newlywed couple, a court heard.
The former 100m champion's Audi A8 smashed into the taxi carrying Peter Ashton, his bride Claire, Lloyd-Ashton, her uncle, Michael Burt, and driver Naeem Akhtar.
Ms Lloyd-Ashton told the court that moments after the collision the athlete exlaimed: "Oh my God! It's all my fault, it's all my fault. I've phoned the police. I've phoned the ambulance."
With that, he collapsed and begun rolling around on the ground in shock, Aylesbury Crown Court heard. Mr Christie, 51, denies dangerous driving on 8 May last year on the A413 Amersham Road in Chalfont St Peter, Buckinghamshire.
Nigel Ogbourn, for the prosecution, said the crash occurred at about 11.30pm. Mr Christie, who lives in Chalfont St Peter, had just driven away from a late-night Tesco Express petrol station beside the A413, where he had gone to buy some milk. Finding the shop closed, he set off on a return journey, taking a slip road back on to the A413, but ended up on the wrong side of the carriageway. Coming towards him in the opposite direction was Mr Akhtar in his Mercedes taxi.
Mr Ogbourn said Mr Christie had been driving on the wrong side of the road for 185 metres before the collision. The taxi ended up on a grass verge and Mr Christie's car ended up sideways in the centre of the road. Both were badly damaged.
When questioned by police, Mr Christie allegedly told officers that he had only recently moved to the area and must have suffered a "lapse" as he looked for the A413. The case continues.