Sergei Skripal, a former Russian spy who was poisoned by a nerve agent in Britain more than two months ago, has been discharged from hospital, England’s health service says.

Skripal, 66, a former colonel in Russia’s military intelligence who betrayed dozens of agents to Britain, and his daughter Yulia were found unconscious on a public bench in the southern English city of Salisbury on March 4.

Sergei Skripl and daughter Yulia endured a long road to recovery.  Photo: AAP/Facebook

Britain has accused Russia of being behind the nerve agent attack and Western governments including the United States have expelled over 100 Russian diplomats. Russia has denied any involvement in the poisoning and has retaliated in kind.

The Skripals were in a critical condition for weeks and doctors at one point feared that, even if they survived, they might have suffered brain damage. But their health began to improve rapidly, and Yulia was discharged last month.

“It is fantastic news that Sergei Skripal is well enough to leave Salisbury District Hospital,” the hospital’s Chief Executive Cara Charles-Barks said in a statement on Friday.

Britain and international chemicals weapons inspectors have said the Skripals were poisoned with Novichok, a deadly group of nerve agents developed by the Soviet military in the 1970s and 1980s.

Russia has denied Britain’s charges of involvement in the first known offensive use of such a nerve agent on European soil since World War II. It has suggested Britain carried out the attack itself to stoke anti-Russian hysteria.