A man accused of murdering his eight-month-old baby has told a jury the boy died after a "bad fall".
Devaun Rose-Turner died after paramedics were called to his parents' flat in Blunham Road, Biggleswade, Bedfordshire on 11 December 2021.
His mother, Shandies Rose, 28, and father, Emmanuel Turner, 33, deny murder, causing or allowing the death of a child, and causing or allowing serious injury to a child.
Mr Turner told Luton Crown Court he had fallen down the stairs while carrying Devaun, adding: "I didn't kill my child."
At the start of the trial last month, prosecutor Mark Heywood KC said Mr Turner told paramedics the little boy had stopped breathing.
Mr Heywood said Devaun had suffered "extensive, catastrophic injuries", including broken bones and a stomach rupture, and could not be saved.
Miss Rose, who has yet to give evidence, had worked at a children's nursery in London but was not working when Devaun died.
Mr Turner, a sub-contractor for HM Passport Office, had been off work because of Covid.
He told jurors he and Miss Rose were going for a walk with Devaun and was carrying the little boy out of the block of flats.
"As I walked down the stairs the light went off," he explained.
"I fell... It was a bad fall."
Mr Turner said neither he nor Miss Rose had made a 999 call after the fall.
"I checked if he had any cuts or any injury; he didn’t have any."
He said he had suggested calling 999 but Miss Rose disagreed, and had told him the boy would be fine after taking his medicine.
He explained that he and Miss Rose fell asleep with Devaun between them, and called 999 in the morning when they woke to find him making "gurgling" sounds.
He said he did not "remember" telling paramedics about the fall.
"I didn't think the fall that I had had affected him. That's the truth... I didn't kill my child."
Mr Turner told jurors how he and Miss Rose began a relationship after meeting in Hackney, east London, in 2019.
"She said she looked after children at a nursery," he said.
"Her plan was one day to own her own nursery."
Mr Heywood has told jurors that many of Devaun's injuries were inflicted in the hours before paramedics arrived and there were signs of others inflicted earlier.
No parent of a child of that age could have "failed to know" about the type of injuries Devaun suffered, he said.
Neighbours had heard noises in the night, he added. They included a "loud thud", an argument, Miss Rose screaming and a baby crying.
The trial continues.