She was grabbed by the offender who demanded the valuables she was carrying.

The victim was walking in the Iceland car park, Albert Road South, Watford at around 1.30am.

The attacker was disturbed by passers by and made off empty handed.

He is described as white, of stocky build, with short dark brown hair and a London accent.

He is believed to be about 5ft 9ins tall and aged 20 to 30.

He was wearing a blue short sleeved top with white writing and dark trousers.

PC Boris Kahn said: "The victim describes two male members of the public who shouted at the offender during the offence and made him run off.

"However, these witnesses have not been traced, so we would strongly encourage them to come forward with any information they might have.

"Also, if anyone saw or knows anything, please get in touch."

Anyone with any information on these crimes should ring PC Kahn via the non-emergency number 0845 33 00 222.

Alternatively, call Crimestoppers anonymously on 0800 555111.