The man behind the Westminster terror attack may have been inspired by a poster of a London bus on the wall of his flat, his former housemate has claimed.

Khalid Masood killed five people when he ploughed a hire car into crowds on Westminster Bridge before leaping out and stabbing PC Keith Palmer to death on the cobbled forecourt of Westminster Palace.

Thousands of fellow officers and members of the public lined the streets to pay tribute to the fallen officer as his funeral cortege made its way through London earlier this week.

Before the attack, Masood, 52, lived in a flat above a restaurant in Birmingham with three other housemates after moving away from his wife and children.

One unnamed housemate believes the large print, showing a red bus in Piccadilly Circus, just streets from where Masood carried out his deadly attack, could have inspired the terrorist.

“For three months I was living next to the terrorist who shocked the world” he told The Mirror. “He was sitting here planning the attack and I believe he may have got inspiration from the picture. Every time he went from his room to the kitchen he passed in front of it.

“It's scary to think this monster was living a few feet away from where I slept. I can't believe that I came so close to true evil.”

The housemate said Masood had no visitors during the time he spent at the flat but was “desperate” to spend time online. He also spent hours lifting weights in his £450-a-month room.

“I believe he wanted access to the internet so he could prepare and plan”, he said. “His room was just a bed, a bathroom and gym equipment, nothing on the walls. Khalid stayed there most of the time. I only really saw him when he was cooking or washing clothes.

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

“He was big and very muscly and always lifting iron to gain strength. He lived in his own tiny world, just the four walls of his room. The way he lived wasn’t healthy, he never saw daylight and he never went outside. He couldn’t find any reason to hold on to life.”

The housemate described Masood as “really calm, almost emotionless” but said he got angry when he thought one of his housemates was smoking cannabis.

He moved into the flat in December 2016 and planned his attack there, disappearing from the property three days before he drove a hired vehicle into crowds in Westminster and fatally stabbed PC Palmer.

Masood, who was born Adrian Elms, grew up in Kent and Sussex. He has two daughters with his first wife, Jane Harvey – the oldest of whom is now 24.

He converted to Islam and changed his name, marrying his third and most recent wife, Rohey Hydara. He moved out of the family home, and into the Birmingham flat, shortly before Christmas.