A Stevenage man’s leg has been ‘smashed to pieces’ after the London terror attacker drove a car into him on Westminster Bridge on Wednesday afternoon – and his family believe he might have been killed had it not been for the rucksack on his back.

Keith Chapman had been walking along the bridge as he headed to a pest control job at St Thomas’ Hospital when the attacker – now named as Khalid Masood – mounted the pavement in a Hyundai and mowed him and many others down.

Brother-in-law Ty Spooner told the Comet that the 61-year-old had no time to react and, had he not been wearing a rucksack on his back, could have sustained a potentially fatal head injury.

The collision has left Mr Chapman, who has lived in the Broadwater area of Stevenage for many years, with serious injuries to his leg and wrist – and he continues to be treated in a London hospital where his long-term partner Linda is also staying so she can be by his side.

Mr Chapman underwent an emergency operation on his shattered leg – which has been broken lengthways – on Wednesday and will undergo another on Monday. He is also due to have surgery on his wrist.

Mr Spooner – who also lives in Stevenage and works as a carpenter – said the family have been told that, while his condition is not life-threatening, they expect Mr Chapman’s injuries to be life-changing.

Relaying the events of Wednesday – in which four people, including a police officer, lost their lives before Masood was fatally shot as he attempted to enter the Houses of Parliament – Mr Spooner exclusively told the Comet: “I was meant to be meeting him at B&Q in Stevenage at 4.30pm to collect some materials. I couldn’t get hold of him, but thought he had probably got delayed on the trains in the wake of the terror attack in London.

“Then his work colleague called me back and told me what had happened.”

Mr Spooner, 57, explained that his brother-in-law remained conscious throughout the ordeal, and remembers vividly what happened.

“He was walking along Westminster Bridge to a job – a route he has been taking for about eight years – when he heard all the commotion,” he said.

“He turned round and the car hit him, throwing him up into the air.

“Lucky isn’t really the right word, but he was lucky he had a rucksack on his back as I think that’s what saved him from smashing his head on the floor. So it could have been even worse.

“It’s not the first time something like this has happened here, but you just don’t expect someone from your family to be involved.

“Living in Stevenage we feel quite safe to be honest and, while there is a bigger threat in London, he just happened to be going across that bridge at that time.

“But it will not stop me going to London, and as a family it’s brought us even closer together.”

The family have asked for their privacy to be respected and do not want to be contacted by other members of the media.