The British government on Thursday sought to defuse a row with Russia after members of the UK security services allegedly said that Alexander Litvinenko, a British citizen and former KGB officer, was murdered in London as a result of “state action”.

“In relation to the stories that appeared earlier this week, no intelligence or security officials were authorised to comment on the Litvinenko case. It is our long-running policy not to comment on intelligence issues. The police and the [state prosecutors] have identified one individual as the individual they believe should stand trial for this murder,” a Downing Street spokesman said.