Detectives investigating the robbery of a cash in transit security guard at a Hampstead Post office have released CCTV footage of the suspect.

The robbery took place on February 16 on Hampstead High Street as a 50-year-old security guard was delivering cash.

According to police, the suspect attacked the guard from behind, pushing him and punching him in the face.

The police statement said: “The victim suffered head and shoulder injuries and was taken by London Ambulance Service to a north London hospital. 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.”

Mohammed Khan, who was posting a parcel at the time, said: “There was a scuffle and then I heard cries and shouts of ‘Stop him!’ and saw a man running away carrying a bag.

“I tried to trip him up and then chased him down the road with the security guard. The guard collapsed after he was struck and I ran as fast as I could half way down the road but I couldn’t keep up.”

He added: “I didn’t know if he had a weapon. When you have a gut feeling you don’t think, you just do it.”