A Tadcaster shop worker was left terror-stricken today after a youth threatened to stab her with a knife unless she gave him money from the till.

Linda Petkus, 45, said she calmly put cash into his rucksack and then followed him out of the shop, before screaming for help.

The incident took place just before 6.30am at the Chocolate Box newsagents in Kirkgate.

The raider, who was wearing a balaclava, fled in the direction of Chapel Street car park, and police officers were on the scene within minutes.

Mrs Petkus was working alone when the teenager entered the shop.

She said: "I asked him what he wanted and he said nothing, so I told him to leave. He then pulled a knife out and said if I didn't put money into his bag he would stab me.

"I felt sheer terror and just did as I was told. When he ran out I went to the door and screamed but nobody was there. I then called the police who arrived very quickly. They were absolutely brilliant."

Selby Police said the suspect is aged about 16, 5ft 4in tall and was wearing a green balaclava, red coat and blue gloves.

DC Pete Masterman, of Selby Police, said today: "This was a nasty incident, bearing in mind the time of day it was, and the fact the staff member was working on her own."

Mrs Petkus, who has worked at the shop for ten years, said: "I'm so cross with myself that I let him do it. I wasn't that frightened, because he was only a kid and I've got a son myself."

Colleague Jane Brown said: "Linda is a very brave lady. She is not the panicking type. I'm sure she was shaken, but she has managed to cover it up very well."

Anyone with information about the incident should telephone Selby Police on 01757 702596.