Russian spy: Foreign minister says Russia willing to help in inquiry

Former Russian military security colonel Sergei Skripal, right, and his daughter Yulia were found unconscious in Salisbury on Sunday

Russia was not involved in the attempted murder of an ex-spy and is willing to help with a UK inquiry, the country's foreign minister has said.

Sergei Lavrov said Russia has not yet been approached by UK authorities investigating the poisoning of Sergei Skripal and his daughter Yulia.

Home Secretary Amber Rudd said the pair remained in a "very serious" condition.

Ms Rudd is visiting Salisbury, where they were exposed to a nerve agent in an "outrageous" attack on Sunday.

The home secretary would not reveal any further details about the substance or how it was administered.

She added police needed to be given space "to do their investigation".

Ms Rudd was seen at the bench where Mr Skripal and his daughter collapsed in the city centre, which remains cordoned off by police.

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On Thursday afternoon there was a "flurry of activity" in Salisbury as investigators wearing protective suits went into Mr Skripal's house, as they try to ascertain where the pair were exposed to the nerve agent.

It is known that Mr Skripal and his daughter had visited the Mill pub and Zizzi restaurant in Salisbury on Sunday afternoon, before they were found near the Maltings shopping centre.

Wiltshire Police Chief Constable Kier Pritchard showed Amber Rudd the bench where Mr Skripal and his daughter collapsed

The graves of Mr Skripal's wife and son at a Salisbury cemetery have also been taped off.

Det Sgt Nick Bailey - who attended the scene on Sunday - is stable and conscious but is "very anxious" about being exposed to a nerve agent.

Former Russian military security colonel Mr Skripal, 66, was convicted by the Russian government of passing secrets to MI6, but given refuge in the UK in 2010 as part of a "spy swap".

Former Metropolitan Police Commissioner Lord Blair said the "extraordinary attack in Salisbury" is a good reason to investigate whether there is a pattern of former British intelligence collaborators dying in the UK.

The attempted murder of Mr Skripal has drawn comparisons to the 2006 assassination of Alexander Litvinenko, who ingested the rare and highly radioactive Polonium 210 in London.

On Tuesday Labour MP Yvette Cooper asked the home secretary to review 14 other deaths that had not been treated as suspicious by UK police, but have reportedly been identified by US intelligence sources as being connected to the Russian state.

Ms Rudd has refused to speculate on whether the Russian state might have been involved in the attack, saying the police investigation should be based on "facts, not rumour".