Cambridge University physicist, David Mackay, in a passionate, personal analysis of the energy crisis in the UK, in which he comes to some surprising conclusions about the way forward. The film is based on his new book Sustainable Energy without the hot air, in which Prof Mackay has calculated the numbers involved for the alternatives to fossil fuels like coal, gas and oil.

He debunks some myths about energy saving - unplugging our phone chargers, does not make any appreciable difference. After showing us what won't work - he goes on to show what will make a difference at home, like turning your thermostat down.

But, his big point is that this will not be enough - individual efforts are not enough. Instead we need to make sweeping national changes to our energy production, and we can't reject everything available to us. If we are going to follow the advice of climate scientists, and get off fossil fuels by 2050, which currently provide 90% of our energy, Britain's main options are wind power and nuclear power. But to make this huge change in our power supply, Mackay says that we have to get building now!

For more information go to David Mackays websitewww.withouthotair.com