Lord Goldsmith said a full extradition request telling the Russians to hand over former KGB agent Andrei Lugovoy will be made shortly.

In a face-to-face meeting with chief prosecutor Yuri Chaika, Lord Goldsmith said he expects the Russian authorities to co-operate.

Lord Goldsmith said: "I have spoken to the Russian prosecutor general to stress that this was a most grave and reckless crime, which killed one man and endangered the safety of many others.

"I have impressed on Mr Chaika that we are seeking and expect constructive and rapid co-operation from the Russian authorities in bringing this suspect before a British court."

Lugovoy was charged with Litvinenko's murder on Tuesday.

The exiled former Russian spy was poisoned with radioactive Polonium-210 in London in November last year.

Lord Goldsmith rejected suggestions made earlier this week that Lugovoy could be put on trial in Russia.

He said: "This murder was committed on UK soil, the evidence is in the UK, a UK citizen was killed and other people put at risk and it is therefore right a suspect should face justice in a UK court."