Card and identity protection firm CPP carried out an experiment in which 20 wallets and purses were dropped in five different cities across the UK.

The wallets contained £10 in cash, as well as photographs, tickets, receipts and stamps to make them look authentic.

They also contained business cards with telephone numbers that linked through to the research team.

But only two out of every 10 wallets that were dropped were returned to their owners, and only half of these still contained the £10.