Supermarket giant Asda has launched an urgent investigation after a used chip fryer was sold to a customer.

Puzzled bosses at the company’s store in St Peter's Street, Maidstone, believe the product may have been swapped by a member of the public for a new one.

The grimy find was made by shopper Sean Bailey who paid £18 for the kitchen appliance only to be left shocked when he opened the box.

The Shepway resident said it was covered in grease and rust and there was even used oil in the box itself.

He said: “It was disgusting. The smell was awful too.”

He was left concerned that, as well as being dirty, the item could have been dangerous as it might have been faulty.

Speaking before Asda suggested another shopper might have been responsible, he said: “It’s terrible to think an item like that could be put back on the shelf for someone else to buy.

“What if it was an older person whose eyesight was not good and they used it and it was faulty and blew up?”

Sean’s wife Sonja had been planning to cook their son chicken and chips when they realised their new purchase was not so new.

She said: “It had been well used and covered in dirty smelly oil and fingerprints.”

The couple took the fryer back the next day and say they were even more unhappy when they complained to customer services and got a very “unconcerned” member of staff.

Sonja said: “It was obvious he wasn’t sure what to say and asked us what we wanted. We asked for another one but they weren't any more on the shelf so he said he would check out the back, he came back and said that there wasn't any so just said you can have a refund.”

Museum volunteer Sean added: “We just wanted to let people know.”

Speaking after being told of Asda’s explanation, the 54-year-old said: “If they are saying someone switched it then security at the door needs to be improved.

“I can’t see someone doing that.”

An Asda spokesman said: “If any customer purchases a product that is not up to the standards they would expect we are happy to provide a full refund providing the customer has their original receipt.

“We don’t sell second-hand appliances and we are looking into how this product ended up on the shelves in this condition.”

Staff believes it could be the case the product was replaced on the shelf by someone who would have taken a new model.