A charity bucket was grabbed from a Salvation Army volunteer, police said.
They said the theft took place in the entrance of White Lion Walk, High Street, at 11.44am yesterday.
Officers said a 38-year-old volunteer was selling charity newspapers when a man grabbed the donations bucket and ran off into White Lion Walk.
Officers believe the offender was male, slim, over 6ft tall and was wearing a grey hooded top with the hood up, as well as a high-visibility vest and black shoes.
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