Chewing gum
Chewing gum takes five years to biodegrade

Wrigley's marks its 100 year anniversary on Tuesday since the popular sweet made its first appearance in a chemist shop in 1911.

But chewing gum, which costs 3p to make a single piece, costs the UK local authorities £150 million a year in cleaning it up - an average of £1 a packet.

The number of pieces of gum currently on Oxford Street is estimated to be 300,000 with this number expected to get higher with the time it takes for chewing gum to dissolve over five years.

Britons chew 100 pieces a year but Wrigley's, alert to the problem, have already invest £5 million into the research and development of a stick of gum that will be able to biodegrade in less than 24 hours.