Scotland Yard has launched an investigation into the recording of phone calls to an anti-terrorist hotline after intercepts were recorded and leaked on the Internet.
The force said it initiated an investigation on Thursday after being made aware that the phone calls might have been breached.
A force statement said: "We are aware of an issue whereby telephone conversations relating to the anti-terror hotline were recorded.
"Officers are currently looking into the matter and appropriate action will be taken."
The announcement from the force came as a recording said to be a "prank call" to MI6 was uploaded on YouTube, attributed to the "hacktivist" group TeaMp0isoN.
The group were said to have compromised a server from Malaysia to record conversations before Trick, the leader of the group, allegedly called MI6 offices in London.
Group leader Trick emailed the Press Association: "The phone denial of service was done via a custom script for Asterisk which was installed on an overseas server.
"The conversation was tapped into via a private phreaking method, their phone system is old and we found a way to get in via basic but private phreaking technique."
In response to the Scotland Yard statement, @_TeaMp0isoN tweeted:
"It wasn't a hard hack at all," said Trick in an exclusive interview with the Huffington Post UK.
"You just have to learn how phone systems work and learn the art of phreaking, which most so-called hackers these days don't even read about. Nor do they even know what phreaking is, except for the underground that is," he said via Skype.
Trick is reportedly a teenage hacker who launched the group in 2010.
The group has been linked to alleged hacking attempts on Facebook and a personal email account linked to a former staff member of Tony Blair's.