A mystery shopper could be sitting on a £18,000 windfall without knowing it.

Tourists Bob and Margaret Southgate are trying to trace a woman who bought a vase from a charity shop in north Norfolk.

The couple, from Towcester in Northamptonshire, visited the Sue Ryder store in Staithe Street, Wells, on Tuesday, May 14.

While there, they spotted a customer buying a vase for £5.

The couple later realised that the vase was similar to one they had seen on the Antiques Roadshow, which was worth about £18,000.

They want to speak to the shopper as they believe she might not know the true value of her purchase.

Mr Southgate said: "In the shop I saw a lady holding a metal vase, which was very heavy and an odd shape.

"I could see a maker's name on the bottom of the vase plus New York marked there. My wife and I left the shop but there was something about the vase that stuck in my mind.

"I had seen the same type of vase on Antiques Roadshow. It had the same art deco look, but more 1960s, was made of medal, and had the same maker's name on it.

"It was valued at around £18,000. At the show it was considered a major piece of art of its kind, and if sold, should go via a leading auction house such as Sotheby's, because there would be international interest. The lady paid £5 for it.

"The only lead I have in tracing her is that she could be in her 30s. She spoke to people in the shop so I think she lived locally and could be a regular customer."

Do you know the mystery shopper? Please email reporter David Bale at david.bale2@archant.co.uk