A military doctor employed by Russia’s GRU intelligence agency was one of the two suspects accused of carrying out the Salisbury nerve agent attack, an investigatory website claimed.

The two suspects in the attempted assassination of ex-Russian spy Sergei Skripal were originally named by the UK authorities as Ruslan Boshirov and Alexander Petrov – although it was made clear that the names were aliases.

The suspect identified as Petrov was actually Dr Alexander Yevgenyevich Mishkin, the Bellingcat group said.

The 39-year-old graduated from one of Russia’s elite Military Medical Academies, the group’s website said.

During his studies he was recruited by the GRU military intelligence agency and by 2010 had relocated to Moscow, where he received his undercover identity – including a second national ID and travel passport – under the alias Alexander Petrov.

Between 2011 and 2018 he travelled extensively under his new identity, Bellingcat said, including making frequent trips to Ukraine.

The last of which was reportedly in December 2013, just ahead of the 2014 Ukrainian revolution which led to Russia’s annexation of Crimea.

For his cover identity he used most of his own details, including his date of birth and first name, and the first names of his parents.

Until September 2014 his home address was registered as the Moscow headquarters of the GRU.

He then moved to an apartment shared with Chepiga.

Bellingcat has already identified Boshirov as Colonel Anatoliy Chepiga – a highly-decorated officer in the GRU.

A spokesman for the Home Office said: “We are not commenting as this is still a police investigation.”

Further details of Bellingcat’s investigation to unmask Mishkin will be released on Tuesday.

The Press Association understands the reported identity is not disputed by UK security services.

The men identified as Petrov and Boshirov are believed to have smeared the highly toxic Novichok nerve agent on a door handle at the Wiltshire home of Mr Skripal on March 4. 

The attack left Mr Skripal and his daughter Yulia critically ill, while Dawn Sturgess, 44, who was later exposed to the same nerve agent, died in July.

The suspects were identified as GRU agents and Theresa May said their actions were not a “rogue operation” and would have been approved at a senior level in Moscow.

The activities of the GRU have come under further scrutiny after the agency was accused of trying to hack the global chemical weapons watchdog which is investigating the Salisbury nerve agent attack.

Officials in the Netherlands, where the Organisation for the Prohibition of Chemical Weapons (OPCW) is based, said four Russians had been expelled after the alleged cyber strike.

British intelligence helped thwart the operation which was launched in April, a month after the Novichok poisoning.

The GRU has also been blamed for a string of cyber attacks targeting political institutions, businesses, media and sport.