Sergei Skripal, the Russian double-agent poisoned in Salisbury, has been discharged from hospital, according to the NHS. Sergei’s discharge follows that of his daughter, Yulia, who was also poisoned in March.

Citing patient confidentiality, NHS England said they were unable to comment on any details about patients, but said: “Treating people who are so acutely unwell, having been poisoned by nerve agents, requires stabilizing them, keeping them alive until their bodies could produce more enzymes to replace those that had been poisoned.”

Following the poisoning on March 4, UK Prime Minister Theresa May stated the government’s chemical laboratory at Porton Down had identified the “military-grade” nerve agents used in the attack as the Soviet Union-developed Novichok.

Speaking in the House of Commons, May suggested that either the Russian government was behind the attack or lost control of its supplies, allowing the “potentially catastrophically damaging nerve agent” to fall into the hands of others.

Foreign Secretary Boris Johnson had backed May’s claims that it was Novichok, explaining to Deutsche Welle that Porton Down scientists had confirmed to him that the nerve agent was used.

But two weeks later, these claims were debunked by Gary Aitkenhead, chief executive of the Defense Science and Technology Laboratory (DSTL) at Porton Down, who said scientists had not “identified the precise source.”

Following Aitkenhead’s comments, the Foreign Office released a statement saying it had been “clear from the very beginning” that Porton Down had identified the type of substance as Novichok.

Novichok refers to a group of Soviet-era nerve agents developed in the 1970s and 1980s. Other countries, including Iran and the Czech Republic, also had versions of the nerve agent, with the former successfully synthesizing Novichok in 2016 alongside the OPCW.

Yulia and Sergei Skripal were reportedly in a critical condition for weeks following the attack, at one point, their doctors feared that they would suffer brain damage if they managed to survive. The pair's health subsequently improved rapidly, and Yulia was discharged from hospital last month.

Salisbury District Hospital Chief Executive Cara Charles-Barks said: “It is fantastic news that Sergei Skripal is well enough to leave Salisbury District Hospital.”

The fact that the Skripals “have been able to leave us so soon after coming into contact with this nerve agent is thanks to the hard work, skill and professionalism of our clinicians, who provide outstanding care to all our patients, day in and day out,” she added. “They’ve demonstrated the very best of the NHS.”

Questions over the Skripals’ current whereabouts have also been raised. Yulia Skripal has not been seen since her release from hospital in early April, prompting claims by relatives that she has been ‘detained’ by the UK and prevented from speaking freely.

Her cousin Viktoria was also denied a visa by the Home Office when she tried to visit the Skripals while they were in hospital. A second attempt made to apply for a visa last month was also denied, with the Home Office saying that her application “did not meet the requirements of immigration rules.”

The British government insists that the Kremlin was behind the attack on the Skripals, who were reportedly poisoned by a nerve agent administered on the door handle of Sergei’s home in Salisbury. Yulia was discharged from hospital five weeks ago, but has not given any interviews since being released. Russia denies any involvement.