A cafe owner was left out of pocket after her detector pen showed that a fake £50 was actually genuine.

Tessa Sommers, who owns The Village Cafe in Bushey high street, realised she had become a victim when she went to check in the £50 note at her bank.

Ms Sommers was serving customers on Wednesday when a man, who she believes was in his 20s, paid for food with a £50 note.

Using a detector pen she had been given from her branch, Ms Sommers checked the validity of it and after testing it, it showed the note was clean.

But when she went to cash in the note, staff told her it was not a real note.

She said: "I felt absolutely gutted, like I'd been mugged off. I was really surprised because the pen I used suggested there was nothing wrong with the note which is why I accepted it.

"I'm urging every small business like mine to be wary and be careful about what they take from people so we are not left out of pocket like I was.

"I am going to invest in an infrared detector to use instead now and I won't be accepting any fifties anymore."

Barclays bank has since compensated Ms Sommers.

A spokeswoman for Barclays bank said: “We would like to thank Ms Sommers for bringing this matter to our attention. As a gesture of goodwill, we have credited her account with £50. There are a number of ways which can be used to check the authenticity of bank notes. Further information can be found at www.bankofengland.co.uk/banknotes”.