Russian spy latest: Home Office refuses to 'confirm or deny' whether Sergei Skripal was still working for MI6

Security minister says it is too early to know all of double agent’s activities - 'When it comes to the investigation, we don’t assume anything'

A Home Office minister has refused to “confirm or deny” whether Russian double agent Sergei Skripal was still working for Britain’s intelligence services.

Ben Wallace said it was a “very longstanding policy of governments” not to comment on such matters, amid suggestions the spy poisoned with a nerve agent in Salisbury was still active.

The security minister said it was too early to know all of Mr Skripal’s activities, saying: “When it comes to the investigation, we don’t assume anything.”

But he added: “It is a very longstanding policy of governments never to confirm or deny whether someone is working for our intelligence services or not.

“There are many reason for that, not least of all the security of individuals and so as not to aid our adversaries.”

Security services previously told The Independent Mr Skripal was not an active MI6 asset, but may have been targeted for "freelancing" for private firms run by former agents.

Mr Wallace also threatened to retaliate “with the full force of the United Kingdom’s resources” against Mr Skripal’s attackers, if appropriate – but declined to say what form that action might take.

His comments come after a report that the Russian spy met his former handler from MI6, the foreign intelligence service, every month in a restaurant in the Wiltshire city.

According to The Times and The Sun, Mr Skripal spoke with the former officer in English and Russian and they also discussed a business he runs in Poland.

It raised the question of whether the double agent, who was jailed for passing Russian secrets to MI6 but later settled in the UK after a Cold War-style spy swap, was still involved in intelligence work.

Security sources have told The Independent he may have been using his intelligence contacts to work for private security firms run by former MI5, MI6 and GCHQ spies.

Mr Skripal, 66, and his daughter Yulia, 33, remain unconscious in a critical but stable condition in hospital, after collapsing in Salisbury city centre last Sunday.

Detective Sergeant Nick Bailey, who responded when the Skripals collapsed, is also in a serious condition, but has improved and has spoken with medical staff.

The investigation is focused on a likely Russia-inspired assassination attempt, but the authorities are still working to determine where the nerve agent used was manufactured.

The Russian government has vehemently denied any involvement in the attack. Foreign minister Sergey Lavrov condemned “pure propaganda, pure fanning of hysterics and hysteria” in Britain.

Amber Rudd, the Home Secretary, will chair a meeting of the Government's emergency Cobra committee at 3pm on Saturday, to receive updates on the police case.

Around 180 troops, including Royal Marines, RAF Regiment troops and chemical warfare specialists, were deployed in the city on Friday after Scotland Yard requested specialist help.

A Ministry of Defence spokesman said armed forces personnel will return to Salisbury in similar numbers on Saturday as the probe and clean-up operation continues.

Mr Wallace told BBC Radio 4’s Today programme: “We will respond with the full force of the United Kingdom's resources, if that is the appropriate and proportionate thing to do.

“We want to make sure that we are effective in whatever our response is. If that is arresting a couple of people and getting them in jail, then that is what we shall do.

“There are lots of things that the United Kingdom can do. It is a powerful country with a powerful economy, powerful allies, powerful military and powerful other capabilities and we shall look at those all.”