A man had part of his skull removed and his heart stopped beating following an unprovoked attack by a complete stranger at Waterloo Station.

David Summerfield, 45, suffered a catastrophic brain injury after a single punch caused him to fall forward and bang his head.

The dad-of-two, from Berkshire, was heading home with a friend after watching a football match in October 2018, when he was targeted in a random attack.

Thankfully a passing doctor was able to perform lifesaving CPR after he was found unconscious, MyLondon reports.

“He hit the floor on his face, there was lots of blood on the floor," said the junior doctor who was first on the scene.

After receiving treatment by London’s Air Ambulance advanced trauma team he was placed in an induced coma before being transferred to The Royal London Hospital.

David is still recovering from the effects of his brain injury and has a huge scar across his head from surgery he underwent but he does not remember the incident.

“I’ve basically had half of my skull removed and replaced,” he said.

“I don’t remember the attack, I don’t remember being in hospital for a month after, I don’t remember the injury."

Speaking of the impact of the incident and the impact of David’s injury his wife Julie said: “We’re very fortunate he’s still here, it’s an horrific injury- and he did die."

David and his family have expressed their gratitude to members of the air ambulance team who provided critical care at the scene.

"They are incredible, I can’t believe that I’ve been saved from the trauma I received," said David.

A London’s Air Ambulance team member who treated David at the scene said it was "critical" they were able to get to David’s side that night and get there so quickly.