A shop assistant has spoken of her anguish after she was attacked while trying to move on a group of youths throwing bottles.

Ann Marchbank was in hospital for three days and had to undergo surgery after her jaw was broken in three places. She also had a bruised eye and swollen nose.

But the psychological effects have been as painful as the attack, which happened two weeks ago at Tesco in Sheep Street, Bicester, where she works.

Miss Marchbank, 38, and a male security guard approached the group of five youths throwing bottles in the doorway of the store and asked them to move on, saying the police had been called.

Miss Marchbank said she then turned away and the ringleader attacked her.

She said: "He headbutted me and my nose just went -- there was blood everywhere. It was in slow motion. He hit me three or four times."

She said the security guard was dealing with attacker's friends, who told him to stop because he was assaulting a woman.

Miss Marchbank said that eventually a female customer managed to pull off the attacker and he ran off towards Bure Place car park.

She believed the offender may have been high on drugs and alcohol, and said he was aggressive and "spoiling for trouble".

The former railway cleaning and maintenance team leader, who moved to the area last August, said: "I grew up in Glasgow and you expect a certain amount of trouble. I worked on the railways for eight years, including Friday and Saturday nights, and never experienced this before.

"I don't sleep well and I don't feel like being on my own. I was protecting my colleagues and members of the public. At the end of the day, I didn't ask for what he did. No man should lift their hand to a woman."

A Tesco spokesman said: "Tesco staff have been told never to endanger themselves. Security measures will as always be in place, including CCTV cameras and a strong security presence."

Police are appealing for witnesses to the assault, which happened at 6.10pm on February 9. The attacker was white, over 6ft tall, slim and had dark hair. He was wearing a black padded jacket, a dark knitted hat, dark trousers and light coloured trainers.

Call Acting Dc Nikki Forster via the police inquiry centre on 08458 505505 or Crimestoppers anonymously on 0800 555 111.