The Post Office has teamed up with children's charity Barnado's to collect unwanted foreign currency from holidaymakers. There is thought to be more than £510 million in foreign money gathering dust in UK homes - an average of £11.07 per adult. In Luton alone there is an estimated £1.6 million lying around in residents' home.

Helen Warburton, head of travel services at the Post Office, said: "We've all come home from holiday and put any leftover coins in the drawer and forgotten about them. But we're inviting people to think about what better use they can put their cash too."

"By bringing all the unwanted currency together, people can make a huge difference to the lives of some of the UK's most vulnerable children. And it's not restricted to coins, customers can also donate unwanted foreign notes and even sterling if they so wish."

Liz Cox, director of fundraising at Barnado's, said: "We're asking people to please take their foreign coins down to the Post Office and make a real difference to the lives of children who really need our help. Barnado's works with 100,000 children and their families throughout the UK who are affected by today's most urgent issues, such as poverty, disability and abuse."

A special Barnardo's collection box is now in place at the Post Office in Luton's Arndale Centre and at participating Post Offices around the country.