MASKED robbers held a gun to the head of an 18-year-old shop worker and pulled a knife on his teenage colleague before making off with thousands of pounds in cash from a 24-hour grocery store.

The three raiders wore bandanas covering their faces when they pounced on their terrified victims as they manned Junction Supermarket, in Junction Road, Archway, at 4.20am on Saturday.

After threatening the two 18-year-old victims with the weapons, they ripped the till out of the socket and carried it out of the shop before disappearing towards Holloway.

Hak Huseyin, chairman of the Archway Town Centre Management Group, said: “I went over to the shop to find out what had happened and I was told they had two members of staff on.

“One was out the front sorting the fruit stall and the other was in the shop.

“Apparently the robbers made off with the whole till, they didn’t even bother to open it.

“I am not sure why the staff didn’t set the PA alarm off, although if someone is holding a gun to your head it is probably the last thing on your mind.”

Stefan Kasprzwk, a former Mayor of Islington who lives in neighbouring St John’s Way, said: “I heard the sirens going and knew something big must be going down.

“We don’t know whether these guys were cruising around looking for somewhere to target or knew some information about the shop, but it’s very disconcerting to think they had a gun.

“It’s obviously a sign of the times with the 24-hour culture nowadays, but it’s difficult to know what the police can do.”

The owners of the shop are believed to be trying to sell up and refused to comment.

Councillor Ursula Woolley (Lib Dem), who represents Junction ward, refused to blame 24-hour licensing for the robbery, but said teenagers should not be working in a shop in the middle of the night.

“I don’t think there’s anything wrong with shops opening 24 hours because they make an area feel safer if you are walking through it at 4.30am,” she said. “But having a shop manned by 18-year-olds at that time seems incredibly dangerous.

“It’s one thing sitting on the till for a couple of hours on a Saturday afternoon, but having 18-year-olds there in the middle of the night seems very unfair on them.

She added: “When I first moved to Archway ten years ago, there were quite a few serious incidents of this type, including a couple of fatal robberies.

“Things are better now but hopefully this is not a depressing return to the bad old days.”

Zara Zaman, co-owner of the large 24-hour Metro supermarket next to Archway Station, said: “I am shocked by the incident – it is quite scary.

“We will be more vigilant in future and make our staff aware. We always have extra staff in the evening and employ a security guard and have 24-hour CCTV coverage. We also never leave more than �50 in the till.

He brother and co-owner Balal Mohammed added: “There should be more police around in the evening because this can be a very busy area.”

A spokeswoman for the Finscley Flying Squad said: “This was a serious incident involving two weapons that naturally has left the victims shocked.

“We would urge anyone with information about the suspects or who witnessed them making off to contact us as soon as possible”.

- Anyone with information should call 0208 351 1751 or Crimestoppers anonymously on 0800 555 111