Dan Hambling, joint owner of Grimsby's Victor Aquatics, described the moment a man entered the store, holding what is believed to be a BB gun hidden in a carrier bag and threatening to shoot if his demands weren’t met.

One member of staff suffered an assault in the attack, although he was not badly injured.

The man was tackled to the ground by Dan, another member of staff and a customer.

Police attended immediately and helped detain the man.

The incident happened at the Victor Street store around 5.15pm on Monday.

“The armed robber shouted ‘I am going to shoot’ at people in the store,” said Dan.

A 19-year-old man was arrested on suspicion of possession of a firearm with intent to cause fear of violence, assault causing actual bodily harm and attempted armed robbery.

Detective Chief Inspector Nicki Miller said: "I would like to commend the staff and member of the public for their brave actions which led to a man being apprehended at the scene.

"I would ask that anyone who may have witnessed this incident or have any knowledge of this incident to contact the police. I would like to reassure the public that incidents like this are not common."

Anyone with information is asked to call 101, quoting log number 400 of February 15.

BB guns are a type of air gun designed to fire spherical projectiles similar to shot pellets of approximately the same size.