He said he then received an email from a Dublin-based private investigator calling himself ''Autarch'', who told Mr Foster he tapped into his mother's phone in December 2002.
That month, The Sun published the ''Foster tapes'', which featured transcripts of Mr Foster talking about selling the story of his links with Tony Blair's wife, Cherie. Yesterday, Mr Foster said he had since had a Skype conversation with the investigator in Dublin, in which Autarch described how he tapped into Mr Foster's mother's phone.
''He said she was using an analogue telephone which they were able to intercept,'' Mr Foster said. Autarch said he discussed the hacking with Sun journalists.
However, this story - at least this version of it - probably isn't true. It is true that the first-generation analogue mobile phone systems like TACS in the UK and AMPS in the States were unencrypted over the air, and therefore could be trivially intercepted using a scanner. (They were also frequency-division duplex, so you needed to monitor two frequencies at once in order to capture both parties to the call.) It is also true that they were displaced by GSM very quickly indeed, compared to the length of time it is expected to take for the GSM networks to be replaced. In the UK, the last TACS network (O2's) shut down in December 2000. It took a while longer in the Republic of Ireland, but it was all over by the end of 2001.
So Foster is bullshitting...which wouldn't be a surprise. Or is he? TACS wasn't the only analogue system out there. There were also a lot of cordless phones about using a different radio standard. Even the more modern DECT phones are notorious for generating masses of radio noise in the 2.4GHz band where your WiFi lives. It may well be the case that "Autarch" was referring to an analogue cordless phone. Because a lot of these were installed by individual people who bought them off the shelf, there was no guarantee that they would be replaced with newer devices. (Readers of Richard Aldrich's history of GCHQ will note that his take on the "Squidgygate" tape is that it was probably a cordless intercept.)
This would have required a measure of physical surveillance, but then again so would an attempt to intercept mobile traffic over-the-air as opposed to interfering with voicemail or the lawful intercept system.
The Daily Beast has a further story, which points out that the then editor David Yelland apologised after being censured by the Press Complaints Commission (no wonder he didn't go further in the Murdoch empire) and makes the point that such an interception was a crime in both the UK and Ireland at the time. They also quote Foster as follows:
According to Foster, the investigator told him that, for four days at the height of Cheriegate, he had been sitting with another detective outside Foster’s mother’s flat in the Dublin suburbs, intercepting and recording the calls to her cordless landline
The Sun hardly made any effort to conceal this - they published what purports to be a transcript, as such.