A Russian agent convicted of spying for Britain was fighting for his life last night amid suspicions he was poisoned in a shopping centre in Wiltshire.

Sergei Skripal, 66, was in intensive care after being exposed to a mysterious substance as he sat on a bench in the centre of Salisbury. A 33-year-old woman who was with him, is also in critical condition. Both had collapsed and were unconscious when they were discovered.

Reports suggest Col Skripal had recently gone to police claiming he was fearing for his life.

The incident comes a little over a decade after the murder of Alexander Litvinenko, the former Russian agent who was poisoned by radioactive polonium in a London hotel.