Nathan Matthews describes 'surreal' moment he cut up Becky Watts's body

Nathan Matthews has described the "surreal" moment he dismembered Becky Watts's body in his bath after killing her when a kidnap went wrong, a court heard.

He repeatedly broke down in tears as he told a jury he did not intend to murder his stepsister.

The 28-year-old frequently started crying and slumped into the witness box holding his head in his hands as he started giving evidence during his murder trial at Bristol Crown Court.

Matthews and his girlfriend, Shauna Hoare, 21, are accused of killing the 16-year-old in a sexually motivated kidnap plot on February 19.

Bristol Crown Court has heard the pair targeted 5ft 1ins Becky due to their shared unnatural interest in petite teenage girls.

They allegedly murdered Becky in her bedroom at her family home in Crown Hill, Bristol, before driving her body to their home in Cotton Mill Lane, Barton Hill, Bristol.

Prosecutors say the couple dismembered Becky in the bath of the terraced property using a circular saw, before packing her body parts in bags, cling film and tape.

These were discovered in suitcases, bags and a blue box in a garden shed in Barton Court - 80 metres from their home - in the early hours of March 3.

Asked to explain what he did to his stepsister, Matthews replied: "I just did it. I tried not to look. I did it and it was just like surreal, that's the only way I could explain it.

"I was just doing what I had to do to protect everybody else finding out that she's gone."

He told the jury he decided to dismember the teenager hours after he had killed her or in the early hours of the following morning.

He had brought her body, in a suitcase, into the front room of the property he shared with Hoare in Cotton Mill Lane, Bristol and left it there overnight.

The following day, he dropped Hoare back at Becky's family home in Crown Hill before driving to B&Q to buy a circular saw, goggles, gloves and masks.

Matthews said he returned home, brought the suitcase up to their bathroom and placed Becky's body in the bath.

He cut her clothes - a short legged onesie and a green jumper - off "so they didn't get caught in the saw".

Forensics officers found no trace of Becky's blood in the bathroom when they searched the property following Matthews' and Hoare's arrest.

"I obviously washed the shower and bath and tiles and everything," Matthews told the court.

"I didn't have anything to put there, I didn't think of buying a sheet or anything."

Matthews said he could not account for marks caused to Becky's neck, near her collar bone, but admitted causing 15 stab wounds and a slash to her stomach.

"I don't know if it was a film or CSI, something about a body when it dies it expands so obviously I did it to, you know, get rid of the body fluid," he said.

"But there wasn't anything."

Matthews said that while dismembering Becky he received and replied to texts from Hoare to "act normal".

Later that day, he returned to collect Hoare from Becky's family home and told her not to use the bathroom as the toilet was blocked.