While families up and down Britain spend Christmas Day empire-building with Monopoly money, two schoolgirls are hoping for more than just £200 for passing Go.

For Rachal Aumann and Maisie Balley are beginning to solve a puzzle which has been branded the biggest jigsaw in the world.

And if they complete it, it could earn them enough money to spend a few nights in the real Mayfair.

We exclusively revealed on Saturday how the friends found a bag containing hundreds of shredded £5, £10 and £20 notes in a rubbish bin as they walked to school in Brighton.

At first the 11-year-olds thought the notes were fake but Bank of England experts confirmed they were real.

The money was found in April last year and since no one claimed it, police ruled the girls can keep it.

They now have to piece together the serial numbers before they can exchange them for new currency.

Rachel and Maisie were handed back the bag of chopped-up cash, weighing about 1kg, at Brighton police station yesterday.

Detective Inspector Bill Warner said no one had any idea how the money came to be in the rubbish. He said: "It is a complete mystery. We have checked lost property and crime files but to no avail.

"I'm sure the girls will have a good go putting the pieces together but they have got their work cut out. It is the biggest jigsaw puzzle in the world."