International problem, personal solution?

So the Environment Secretary David Miliband tells us the concept of a personal carbon credit card is an idea whose time may

Flights would prove expensive on your carbon credit card

have come.

But how would it work?

Well who better to ask than the Royal Society for the Arts - who Mr Miliband says have been doing their own work on personal carbon trading.

We spoke to Matt Prescott, the project's director, and asked him first of all if personal carbon trading could actually work.