DETECTIVES are hunting an armed robber who stole "a substantial amount of cash" from a North Lincolnshire shop early on Saturday morning.

The raid took place just after 7am at the Spar store in Waterside Road, Barton-Upon-Humber.

The offender, a male, said to be about 6ft tall, is believed to have been loitering around the area about 20 minutes before entering the premises.

The man, who was wearing light-coloured trousers, produced something resembling a metal bar and demanded cash and cigarettes from the terrified female assistant, who was on her own in the shop at the time.

Claire Curtis, 26, who is also employed at the store, said: "She was bent down doing the papers when a guy came in.

"He had a big metal bar or something like that in his hand.

"He said 'I am not going to hurt you – just give me the money'."

He then snatched the cash.

Claire said her terrified colleague was told to get a plastic bag and to fill it with cigarettes.

But, she said: "As she was doing that, he saw a customer was coming in and it spooked him and he ran off."

The assistant, Claire said, was unharmed, but was left "very shaken" by the experience and she was recovering from her ordeal at home.

"It was a shock. She just looked up and saw this man threatening her with this metal bar.

"It's quite shocking. You don't expect it to be happening down here. You hear of it in other places, but not here.

"It's not yet sunk in."

Claire, who has only worked at the store for a couple of weeks, said she had been delighted with the response from their customers.

She said: "It's been really nice with all our regular customers coming in and saying I hope she is all right and being really shocked by it all."

At the time of going to press, no arrests had been made.

Anyone with any information about the crime or the offender should call police on 0845 6060222, quoting log 145 of March 13.