Can a paper helmet protect cyclists' heads?

Half a million cycle trips are made each day in London, and a recent spate of deaths has put cycle safety at the top of the agenda.

One thing that can be important for safe cycling is a well-fitted cycle helmet.

Most helmets are made from polystyrene, but Dr Ayan Panja has been finding out how humble sheets of paper - arranged in an ingenious way - can offer even more protection.