A supermarket chain has launched an investigation after a shopper discovered a “sharp and solid” bone in his sandwich – and raised fears that a child could have been seriously injured by the fragment.

The Downley resident – who did not want to be named – said he bought a pulled chicken sandwich on Monday lunch time at the Tesco Esso Express in Marlow Road, High Wycombe.

But after tucking into his lunch, he discovered an inch-long bone inside – and said he was “lucky” not to have been hurt.

After returning to the store where he bought it from, he was sent to Tesco in the Eden Centre to complain – and has since been sent a £5 voucher by the chain.

He said: “I'm not after any money but I think it is a bit of an insult. What can I do with that – buy two more of the same sandwich? I'm lucky I wasn’t seriously injured.

“I dread to think what might have happened if it was a child who was eating it – it could have put them in hospital.”

A Tesco spokesperson said: “There’s nothing more important than the safety of our products, and we have robust food quality processes in place during preparation and packaging, so it’s not immediately clear how this may have happened.

“We have asked [him] to return this product to store and will investigate with our supplier.”