London terror attack Khalid Masood
Khalid Masood, who carried out the London terror attacks Stefan Rousseau/PA

Detectives who are piecing together the background of the Westminster terrorist Khalid Masood have discovered a string of aliases used by the 52-year-old.

Masood was described by Met Police as a criminal with a 20-year record of offending, who had once been investigated for extremism but was assessed as low risk.

His first conviction was in November 1983 for criminal damage when he was 18. His most recent offence was in 2003 when he was convicted for possession of a knife.

There was no prior intelligence about his intent to carry out a terrorist attack and he had never been convicted for any terrorism offences.

Prime Minister Theresa May described him as a "peripheral figure" who was once investigated by MI5 in relation to concerns about violent extremism, in a televised speech to the House of Commons on 23 March.

Reports have emerged that his birth name was Adrian Russell Ajao. He also used the name Adrian Elms.

As police search for any evidence of a wider conspiracy, eight people remain in custody after properties across the UK were raided.

The death toll from his assault on the capital rose to four on Thursday night when a 75-year-old man, named as Leslie Rhodes from Streatham, south London, had his life support withdrawn at King's College hospital.

Masood is thought to have hired a Hyundai 4x4 vehicle in Birmingham before driving to Brighton. The Sun reported that he stayed at the £59-a-night Preston Park Hotel, where he falsely gave his profession as a teacher.

The paper reported that Masood had told staff he was "off to London today" and that the capital was not "like it used to be".

He was believed to have been living in the West Midlands, according to the Metropolitan police.

Terrorist organisation Isis claimed responsibility for the attack yesterday (23 March), describing Masood as a "soldier of the Islamic State".