An all-female team of Serco guards escorted a known troublemaker at Blackfriars Crown Court on the day he kicked one of them in the head causing her "catastrophic" injuries, a court has heard.

Humphrey Burke, 23, fatally attacked 54-year-old Lorraine Barwell as he was being led from holding cells to a waiting prison van on June 29 last year.

During a hearing at the Old Bailey, Burke was found unfit to plead to a charge of murder as he has since been diagnosed with paranoid schizophrenia.

Opening a trial of facts, prosecutor Duncan Penny QC said Burke, formerly of Friars Wharf, Oxford, had been "unpredictable" at previous Blackfriars hearings where he had pretended to faint, collapse and go limp.

On the morning of the attack, his file had been marked "three-man unlock" and Mr Penny said "some of the staff" were aware of details of his previous behaviour.

By 1pm, he had appeared in the dock and returned to the holding cell ahead of his removal back to HMP Thameside.

Mrs Barwell and two other female guards went to his cell to take him to the prison van.

One of them was on her first day in the job and was "work shadowing", Mr Penny said.

The victim had handcuffed herself to the defendant, as per standard procedure, when he collapsed to the ground.

Other staff arrived and Burke was taken into the corridor and his handcuffs were removed.

Three male officers tried to get him on his feet but he began to struggle and was restrained and handcuffed behind his back.

Mr Penny said: "As he was standing up, the defendant was bent forward whilst Lorraine Barwell was standing in front of him attempting to control his head.

"Once on his feet, the defendant was kicking behind him without making contact. He then appears to have lunged forwards and managed to kick out twice towards Lorraine Barwell who was standing in front of him. He seems to have kicked at her twice, the latter kick connecting with her head."

The first kick knocked her to the ground and while she was on her knees in front of Burke, he landed a second blow to her chin, the court heard. She died in hospital from a brain haemorrhage two days later.

Mr Penny told the court that at the time of the attack, a psychiatric report had been prepared on Burke but no definitive diagnosis of mental illness had been made.

He had pleaded guilty to the attempted robbery of two bookmakers in Islington in 2014 as well as arson and criminal damage.

In one of the incidents, he had threatened staff with a claw hammer and damaged Perspex screens and in the other, he had set fire to a shop using white spirit.

Mr Penny told jurors they would hear from witnesses, including Martin Walker, who was among those trying to get Burke to his feet.

The witness had described a "loud crack" as Burke landed a "ferocious kick to the jaw".

Prison officer Delft Warden heard a "proper thud" leaving Mrs Barwell on the floor with her eyes rolling back, the court heard.

Afterwards, the defendant allegedly said: "I did not intend to murder that woman. That's all I have to say."

Jurors were told they would only have to decide whether Burke did the alleged act, not whether he was guilty.