British police are investigating the murder of a man believed to be a British spy, after a body was found in a flat near intelligence headquarters in London.

The corpse, which was reportedly found stuffed into a bag and left in a bathroom, has not yet been formally identified.

The man worked as a communications officer for the country's eavesdropping agency GCHQ, and was on a secondment to MI6, Britain's foreign intelligence service, but it was not clear whether he was employed as a spy.

Police and the foreign office, which oversees MI6, have not confirmed the victim's details.

Sim cards 'laid out'

Scotland Yard opened a murder inquiry on Wednesday, two days after the body was discovered in an apartment in Pimlico, 1.6km from MI6 headquarters.

Police entered the residence on Monday afternoon following reports that the occupant, who was said to have been in his 30s, had not been seen for some time.

The Daily Mail reported that police officers found the man's mobile phone and a collection of sim cards "carefully laid out" inside the property.

Scotland Yard refused to say whether there were signs of a struggle or how
the man may have been killed, but said suicide had been ruled out.

Paul Brennan, Al Jazeera's correspondent in London, said the man could have been dead for up to two weeks.

"A post-mortem is taking place today, at which the cause of death will be ascertained, it is hoped. But a stabbing appears to be the version that is coming from police sources at the moment."

He said the fact the death was being investigated by the homocide squad rather than an anti-terror or special branch of the police suggested the murder may not be directly related to espionage.

A police source told the Press Association: "The suggestion there is terrorism or national security links to this case is pretty low down the list of probabilities."

'Den of spy activity'

If reports of the victim being a spy prove true, it will be the latest murder of someone linked to secret services since the killing of Alexander Litvinenko in 2006.

Litvinenko, a former KGB agent turned Kremlin critic, died in hospital after being poisoned with the radioactive substance polonium-210.

Britain has been known as a den of spy activity since the Cold War, with some 4,000 British intelligence specialists alone working for MI6, GCHQ or Britain's domestic security agency, MI5.

In 1978 Georgi Markov, a Bulgarian dissident, died of blood poisoning after he was stabbed with an umbrella at a London bus stop.