Chemical security

Inside Britain's secret weapons research facility

As Porton Down marks its 100th anniversary, what really goes on inside Britain's most secretive and controversial military research base?

Porton Down - also known as the Defence Science and Technology Laboratory - is where much of our top-secret military research is concentrated. It has a budget of £500m a year and employs more than 3,000 scientists. It is the most controversial, most misunderstood and, some say, most-feared scientific institution in Britain. Though many will have heard of Porton Down, few will have much idea about what goes on inside.

So I was delighted when I was invited to go behind the fence, make a documentary about the research that goes on there.

Set in more than 7,000 acres of English countryside, Porton Down was created 100 years ago in response to the German gas attacks of World War One. The first of these attacks against British troops involved the use of chlorine. Thousands of soldiers, who had no idea what they were facing, suffered severe chemical burns or died in agony. Chlorine was soon joined by mustard gas and phosgene.