By Leah Richardson

The Top Secret Porton Down research facility in Wiltshire has leapt to the public consciousness over the last few months, with its involvement in two high profile poisoning cases in the county.

But what do we actually know about it?

The centre was set up in 1916 at the height of the First World War as a chemical weapons research facility, tasked with finding a way to combat gas used by the German army as a weapon.

There are a number of different organisations at the site near Porton, but the name is generally used to mean the Defence Science and Technology Laboratory.

Since 1916 over 20,000 volunteers have taken part in studies at Porton Down, helping scientists develop both protective countermeasures and antidotes to chemical weapons.

There have been tragedies. In 1953 a participant in an experiments, aircraftsman Ronald Maddison tragically died from a few drops of the nerve agent Sarin, which was applied to his forearm through two layers of cloth.

Nine years later in 1962, one of the research scientists at the site Geoffrey Bacon is reported to have died of the plague.

In 2001, the government launched a medical investigation into the health of 20,000 volunteers who took part in the trials at the facility.

Porton Down’s work is now completely defensive in nature, researching countermeasures to chemical and nerve weapons – it does not develop or produce chemical weapons