The terrorist responsible for the Westminster attack has been named by police as Khalid Masood, as further details continue to emerge about the identity of the killer.

The 52-year-old was born Adrian Russell Ajao in Dartford, Kent, and most recently lived in the West Midlands. He is understood to have converted to Islam in prison, having spent time behind bars for violent crime, at which point he also went by the alias Khalid Choudry.

Former neighbours said they were shocked to learn of his involvement in the attack, telling The Independent he was a "nice guy" who had a "normal family".

He is thought to have had young children, although there were conflicting reports regarding how many. Some acquaintances said he had three, and some four.

Scotland Yard said Masood had previous convictions for assaults, grievous bodily harm, possession of offensive weapons and public order offences. In one attack he is reported to have stabbed a man in the face, leaving him needing cosmetic surgery.

His first conviction was in November 1983 for criminal damage and his last conviction was in December 2003 for possession of a knife. He had not been convicted of any terrorism offences, but police said he was known by a number of aliases.

The Metropolitan Police and Sussex Police did not confirm further details of Masood's convictions or prison sentences to The Independent.

Although Masood had never been a part of a terror plot himself, he had been associated in the past with suspected Islamist terrorists, security sources told The Independent.

His indoctrination may have begun through meeting extremists while in prison, they said.

Masood, who was described as a bodybuilder, was reportedly brought up by his single mother, Janet Elms, in East Sussex. The Daily Mail reported his mother married a man named Phillip Ajao when Masood was a young boy.

At times, he is understood to have gone by the name Adrian Elms. The Home Office said it was still investigating how all Masood's aliases fitted together.

Westminster terror attacker named as Khalid Masood

He is thought to have made trips to London from the West Midlands to plan his attack and had stayed in the capital during his visits. Apart from Kent and Birmingham, he had lived for brief periods of time in Luton and east London.

Three people were killed when he ploughed a car through pedestrians on Westminster Bridge, before storming the Parliamentary estate. He was then shot dead.

He is thought to have regularly attended a mosque in Birmingham, although security sources refused to discuss details because, they said, it was part of ongoing investigations.

Scotland Yard said eight people – five men and three women – had been arrested in London and Birmingham and were being held on suspicion on preparing terrorist acts.

Seven of the suspects, aged between 21 and 39 were arrested overnight. A 58-year-old man was arrested in a separate raid.

Detectives are continuing to search a number of addresses in relation to the attack, including three properties in Birmingham, one in east London, and one in Carmarthenshire, Wales.

Emergency services at the scene while two knives lay on the floor outside the Palace of Westminster, London, after a policeman was stabbed and his apparent attacker shot by officers in a major security incident at the Houses of Parliament (PA wire)

Masood had been living at a property in Birmingham's Winson Green neighbourhood with a woman and young child, but left abruptly in December, according to his former neighbours.

He is also thought to have had an interest in bodybuilding, and to have claimed to be an English teacher.

Shocked residents in Winson Green, described a man who had appeared the perfect suburban neighbour.

“He washed his car, mowed his lawn,” said Ciaran Molloy, 27, a mailing machine engineer who lived overlooking Masood’s new-build house. “He was quite friendly, polite in every interaction.

“It’s a shock to know he did what he did. It’s a shock to know he lived across the road.”

Mr Molloy said Masood would mostly be seen wearing “gym clothes, a tracksuit, although I did sometimes see him in Muslim dress.”

He added: “He had a missus, kids – I think it was two girls, about seven or eight, who you’d see wearing school uniform, and a son of about three.”

Other neighbours said Masood’s wife tended to wear grey Muslim-style clothing, while keeping her face uncovered.

Parliament holds a minute-long silence in memory of the victims of the Westminster attack

One local child said he had once played football with Masood and another relative, who was aged about seven, in Masood's front garden during the last summer holidays.

The boy said: "He was a nice guy, he even taught us how to play football, passes and touches".

Kaodi Campbell, 25, a student at University College, Birmingham, said: “He was a nice guy to me. He helped me jump start my car a few times. He was happy to lend me a set of jump leads.

“It’s mad that it was him. They did keep themselves to themselves, but they seemed like a normal family.”

Masood and his family, she added, moved out at the turn of the year, without telling any of their neighbours they were leaving.

“I just noticed one day that they had moved out.”​

Earlier, Prime Minister Theresa May said the attacker was born in Britain and had previously been investigated for suspected extremism by MI5.

He was once investigated in relation to concerns about violent extremism some years ago but was a "peripheral figure".

The case is "historic" and the attacker was "not part of the current intelligence picture," Ms May added.

In pictures: Westminster attack Show all 9 1 /9 In pictures: Westminster attack In pictures: Westminster attack An air ambulance lands after gunfire sounds were heard close to the Palace of Westminster in London PA wire In pictures: Westminster attack MPs wait until the situation is under control in Westminster. 'The alleged assailant was shot by armed police,' David Lidington, leader of the House of Commons, told the house. BBC News In pictures: Westminster attack Crowds gather in Westminster after shooting incident, which police are treating as terror attack BBC News In pictures: Westminster attack Police were also called to an incident on Westminster Bridge nearby AP In pictures: Westminster attack Early reports indicate the car, which mounted the pavement on Westminster Bridge and mowed into around a dozen people, was the same vehicle which then rammed into the railings of the Palace of Westminster, just around the corner Reuters In pictures: Westminster attack Security sources described the suspected assailant as a middle-aged Asian man, who is understood to have left the car before attacking a police officer with a seven-to-eight inch knife PA wire In pictures: Westminster attack Police have asked people to avoid the immediate area to allow emergency services to deal with the ongoing incident AP In pictures: Westminster attack One woman has died and a number of others, including the police officer, have been hurt, according to a junior doctor at St Thomas' Hospital Reuters In pictures: Westminster attack At least three gun shots were heard by those inside Westminster, and proceedings in the House of Commons have been suspended AP

Isis claimed the attacker was a "soldier of the Islamic State" when it claimed responsibility for the attack.

However the group did not name him and did not provide any further details. The terrorist group regularly claims “credit” for atrocities and there is no evidence at present to verify the claim.

No video has yet surfaced of him pledging adherence to Isis and its leader Abu Bakr al-Baghdadi, which has become the practice of those carrying out attacks on behalf of Isis.

The Enterprise rental car company said the vehicle used in the attack had been rented from its Spring Hill branch in Birmingham, which is located in the West Midlands.

"An employee identified the vehicle after seeing the licence plate in an image online. We ran another check to verify, and immediately contacted the authorities," said company spokesman John Davies.

Masood had told the firm that he was an English teacher on Tuesday and later called the company to say he was likely to cancel the hire, but they did not hear from him again.

About 40 people were injured in the attack and around 29 remain in hospital.

Five people remain in a critical condition and two have life threatening injuries.

Police had given the death toll as five but revised it to four.

The casualties included 12 Britons, three French children, two Romanians, four South Koreans, one German, one Pole, one Chinese, one American and two Greeks, Ms May said.

The attack took place on the first anniversary of attacks that killed 32 people in Brussels, and resembled Isis-inspired attacks in France and Germany where vehicles were driven into crowds.

It was the deadliest attack in Britain since 2005, when 52 people were killed by Islamist suicide bombers on London's public transport system.