Police have released CCTV footage showing the dramatic moment a security guard attempted to fight off a robbery suspect after being attacked from behind. The guard, who was delivering cash to a post office in North London, swung his helmet at the assailant before leaping over a sofa and chasing after him.

Detectives have released video footage of the incident, which took place in the High Street, Hampstead, at 1.40pm on 16 February. They wish to speak to anyone who can identify the hooded man, who police say pushed the security guard from behind and punched him in the face.

The guard, a 50-year-old man, suffered head and shoulder injuries and was taken by London Ambulance Service to a North London hospital. He was released later that day.

The suspect is described as a tall white man, wearing a black padded, hooded coat. Anyone with any information should contact the Flying Squad on 020 8785 8655 or Crimestoppers anonymously on 0800 555 111.