THE former head of MI6 has said the government was wrong about how much security Russian former spy Sergei Skripal needed while living in Salisbury.

Sir John Sawers said the location of Mr Skripal and his daughter Yulia is still a closely guarded secret.

When asked by BBC's Panorama if Mr Skripal should have been better protected, former head of MI6, Sir Sawers said: “I think this question of what level of protection you provide for people who have been released and swapped in this way, it varies from individual to individual.

"Now clearly we got that calculation wrong, that the threat against Sergei Skripal was much higher than we had expected, because we hadn’t expected the Russians to go back on a Presidential pardon.”

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The British Government has accused Russia, specifically it’s military intelligence agency, the GRU of responsibility for the attack.

Russia denies any involvement in the Salisbury nerve agent attack.

Panorama: Salisbury Nerve Agent Attack - The Inside Story will be shown on BBC One tonight (Thursday) at 8pm.