A man accused of crushing a toddler to death with his car seat has told jurors he did not know anything was wrong until he got out of the vehicle.
Stephen Waterson, 25, denies the manslaughter of Alfie Lamb last February.
Mr Waterson told the Old Bailey he had moved his car seat back "a few inches" but thought Alfie, who was in the footwell behind him, was fine.
Alfie's mother Adrian Hoare, 23, also denies manslaughter.
The pair had been travelling with Emilie Williams and Marcus Lamb, who was driving, and were returning from a shopping trip to Sutton on 1 February 2018.
Mr Waterson, who lives with Ms Hoare in Adams Way, Croydon, told the court Alfie's body was floppy and heavy when he picked him up out of the car.
He said at that point he thought the toddler was "joking around" but then realised Alfie was seriously hurt.
Jurors were previously told Alfie's cause of death was ischemic brain injury caused by deprivation of blood or oxygen and compression asphyxia.
When asked why he had initially given a false name to the police Mr Waterson said he had panicked.
He also told jurors he had "gone along" with a fictitious story given by Alfie's mother about what happened.
The trial continues.