Amid the ongoing investigations regarding an alleged Russian spy ring operation in the United States, sources says as many as 300 Russian spies may be operating in the United Kingdom, Press TV reported.
The figure was deemed 'credible' by Edward Lucas, an expert and author on post cold war spying techniques, Sky News reported on Sunday.
"I think what really interests them would be things like, what's the foreign policy of this government going to be under Clegg and Cameron?" he said.
While Lucas believes the spies might be analyzing issues such as the British foreign policy, Alexander Nekrassov, a Russian analyst, says that "there are probably hardened spies, professionals and that would be quite a small number, who would be looking for recruitment, that's the ultimate goal of any intelligence service."
According to Sky News, although intelligence gathering has shifted from issues relating to nuclear weapons secrets to geo-political issues, espionage is still a major issue decades after the cold war.
The Former Head of MI5 Dame Stella Rimington, has recently accused Russia's security services of being as active in Britain today as they were during the Cold War, The Telegraph reported.
Russia has "a very large and well-resourced intelligence community," which is still a threat to British security and economy.
The remarks came after a series of arrests in the US that led to the dismantling of an alleged 10-year Russian spy ring.
On Friday, three more suspected Russian spies appeared before a court in the US.
In June alone, police detained 10 people in the US on charges of conspiracy and working as unlawful agents of a foreign government. If convicted on such a charge, the sentence carries up to five years imprisonment.