A killer who raped a complete stranger in Neasden before stabbing his ex-partner to death claimed that he was ordered to carry out the killing by a voice in his head called ‘Tommy.’

Jurors at the Old Bailey heard Marvin Samuels, 31, of Conduit Way, Stonebridge, carried out the sex attack on the 42-year-old dog walker in Welsh Harp before killing and Sharlana Diedrick, 32, a few hours later in Wybourne Way, near his home on September 29 last year.

He admits to carrying out the offences but claims his mental illness diminished his responsibility.

Psychiatrist Dr Nadji Kahtan told the court he was convinced Samuels’ condition made him not guilty of murder.

Jurors were told Samuels took an overdose as a nine year-old, was referred to a consultant child psychiatrist at the age of 13 and diagnosed with at anorexia at 15.

He was completely out of his mother’s control and began amassing a series of convictions for offences including battery against Ms Diedrick.

He claimed he thought the first victim was a spy because she was wearing a hat and glasses and raped her and left her for dead.

Later that evening he agreed to meet up with Ms Diedrick, who he described as his ‘babymother’, and stabbed her 16 times as she sat in her car.

He claims the voices in his head were saying: ‘’Kill her, kill her.’

Jurors also heard Samuels attacked a fellow inmate with a razor in the exercise yard at Belmarsh prison shortly before being transferred to Broadmoor Hospital where he attacked another patient with a badminton racket and a member of staff.

Samuels has admitted rape and causing grievous bodily harm with intent, but denies murder and attempted murder.

The trial continues.