Westminster victim Travis Frain relives moment he was struck by attacker Khalid Masood's car

Westminster attack victim Travis Frain has relived the moment he was flung over Khalid Masood's car bonnet as he told ITV's Good Morning Britain what had made him revisit the scene of last month's attack.

The teenage student said he had been "enthralled" on his phone after watching Prime Minister's Questions with course-mates when a friend saw the pavement-bound vehicle hurling towards them.

"We'd just left Parliament and I was walking across the bridge with a couple of friends," he said.

"I was texting someone at the time and one of my friends said 'Travis, look'."

Travis said when he looked up he saw Masood's 4x4 car around five metres away, giving him no time to avoid the collision.

He said the fact the vehicle was so close may have actually helped him survive the impact.

"I didn't really have time to react," he explained. "My body didn't have time to tense up and was thrown almost like a ragdoll over the bonnet.

"I landed on the left side and my head was actually cushioned by a friend ... whereas obviously if it had landed on the concrete with the same force that the rest of my body had we don't know what could have happened."

The 19-year-old said the moments after the attack largely remain "a blur" though he remembers walking around - despite breaking his leg - and picking up his phone before his eyes "just blacked out".

Candles were lit on Westminster Bridge in the wake of the attack for the victims. Credit: PA

The teen had emergency surgery after breaking his leg, arm and fingers in the March 24 attack, which would claim five lives before Masood was shot dead outside Parliament.

His account of the attack came as the new Metropolitan Police chief Cressida Dick said an armed police officer may not necessarily have intervened to stop Masood earlier.

The collision with Masood's car has left Travis with his arm in a cast and his leg in a brace for several months, but feeling fortunate to be alive.

"It sounds weird (but) I do feel very lucky," he said.

Travis's recovery at London's King's College Hospital saw him spend time with Prince Charles in a bedside visit commemorated with a photograph the teen shared on his Facebook page.

The university student, seen with Prince Charles and with his dog before the attack, said he appreciated the visit the royal visit. Credit: Handout

He said he appreciated the 10 minutes with the future king.

"It was really nice of him," he said. "He was actually quite laid back and asked how I was doing."

Travis, who is studying politics and history at university in Lancashire, has revisited Westminster Bridge twice since his attack as he insisted that terror would not deter him from visiting the capital.

"I wanted to see it again," he said, adding that he did not "get flashbacks" as he retraced his steps.

"It's not going to put me off London. As weird as it is, life goes on."

Travis said he believed the acts of terror had become increasingly "desperate" but were doomed to fail.

"This one guy (tried) to shut down London and he managed to shut down a bridge for 24 hours. That's it. Life went on as usual," he said.

"Obviously it's drastically changed a lot of people's lives, there are people who can't be brought back sadly. (But terror attackers are) getting desperate now and I think it's showing."