Islamic State's "Jihadi John" has been named in reports as Londoner Mohammed Emwazi, who prayed at the Greenwich Islamic Centre in Plumstead.

According to the Washington Post and the BBC, Emwazi has been identified by friends and others familiar with his case.

It is claimed he was raised in a middle-class neighborhood in west London and on occasion prayed at a Greenwich mosque.

The IS frontman, who has appeared in a series of shocking videos in which hostages, including British aid worker Alan Henning, are brutally murdered, is reported to have grown up in west London and graduated from university with a degree in computer programming.

Scotland Yard has refused to confirm the reports.

In a statement, Greenwich Islamic Centre said today: "It is our clear understanding that whilst he might have visited the mosque for prayers, like tens of thousands of people do each month, we have no knowledge of any such visit made by him, and there has never been any link whatsoever between the centre and Mohammad Emwazi.

"We condemn in the strongest terms any form of extremist ideology and would like to remind our communities and press about the efforts and struggle this centre had to go through in the past to get rid of people like Omar Bakri, Anjem Choudhry, Usman Ali and their followers.

"Furthermore, we express our sadness that yet another young member of our society has allegedly ended up radicalised in the hands of extremists, which is totally and utterly against the teachings of Islam."

And worshippers at the Plumstead Road centre said they thought Emwazi was "unknown" to the mosque there.

One member of the management committee said: "We are not aware of anything about it.

"We have about 4,000 coming for Friday prayers. We can't identify every one of those 4,000, but he was an unknown person with no connection to the mosque.

"It is very shocking but we have never heard anything about this guy."

Commander Richard Walton, head of the Met's Counter Terrorism Command, said: "We have previously asked media outlets not to speculate about the details of our investigation on the basis that life is at risk.

"We are not going to confirm the identity of anyone at this stage or give an update on the progress of this live counter-terrorism investigation."

The man known as Jihadi John rose to notoriety when he first appeared in a video posted online in August, in which he appeared to kill the American journalist James Foley.

Dressed in all black with a balaclava covering all but his eyes and the ridge of his nose and a holster under his left arm, he reappeared in videos of the beheadings of US journalist Steven Sotloff, British aid worker David Haines and American aid worker Peter Kassig, as well as footage of Mr Henning's death.

And last month, the militant appeared in a video with the Japanese hostages Haruna Yukawa and Kenji Goto, shortly before they were killed.

A detailed Washington Post article claims Jihadi John is in fact Kuwaiti-born Emwazi, who it says travelled to Syria around 2012 before later joining IS, which has taken control of large swathes of the conflict-torn country, as well as territory in neighbouring Iraq.

The article claims Emwazi started to radicalise after a planned safari in Tanzania following his graduation from the University of Westminster was brought to an abrupt end when he was detained on arrival in Dar es Salaam and deported the following day.

It is claimed that Emwazi told friends he was flown to Amsterdam where an officer from MI5 accused him of trying to reach Somalia, where the militant group al-Shabab operates.

Downing Street declined to confirm or deny that the reported name was known to the intelligence and security services.

Asked if David Cameron was concerned about Emwazi's name being reported, a No 10 spokeswoman said: "The Prime Minister would be concerned about information being put into the public domain at any time that might jeopardise ongoing police or security investigations or the safety of British citizens.

"There is an ongoing investigation. It is absolutely right that we allow the police and security agencies to do all they can to bring those responsible to justice and to help keep British people safe."

A statement from the International Centre for the Study of Radicalisation at King's College London said: "We believe that the identity and name published by the Washington Post and now in the public realm to be accurate and correct.

"'Jihadi John' is not special, in the sense that all the foreign fighters have tried to hide their identity by using pseudonyms or literally by masking themselves.

"The fact that 'Jihadi John' has been unveiled in this manner demonstrates that whatever efforts are made, the ability to mask one's identity is limited or in fact impossible, and their true identities will eventually be revealed.

"This demonstrates what we have long said about radicalisation, that it is not something driven by poverty or social deprivation. Ideology clearly plays a big role in motivating some men to participate in jihadist causes.

"British fighters have clearly demonstrated that they are not in this conflict to take a back seat. They are full participants in this war, operating as suicide-bombers, hostage-takers, and executioners."