It is a jigsaw that would drive even the most patient of puzzle fans to distraction.

But binman Graham Hill has been told the bundle of cut-up £10 and £20 notes he found in a Lincoln litter bin could be exchanged for new ones - if he can piece the bits together.

Lincolnshire Police launched an investigation and held the money for six months after Mr Hill, from Gainsborough, discovered it in Lincoln City Square.

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But the force gave him it back when no one came forward to claim it.

Detective Constable Nick Cobb said: "Following extensive inquiries, there was no evidence that the money was stolen or linked to any criminal activity.

"This was a very unusual case and despite our inquiries the circumstances of why and how the money came to be torn up and put in the bin remains a mystery."

The value of the notes has been estimated at around £10,000 but Mr Hill faces a tough task, police said.

The currency has been chopped into small pieces and it appears no serial numbers have been left intact.

"He'll have a job making some money out of it," a force spokesman said.

A Bank of England spokeswoman said: "Providing the bank notes meet the evidence requirements, then an application for reimbursement should be successful."

Speaking shortly after he found the money, Mr Hill told the Lincolnshire Echo: "I was gutted when I looked in there and saw it all cut up."