The company that carried out the security sweep of the offices of the Garda Siochana Ombudsman commission late last year has rejected a claim that a wifi signal from a coffee shop explained one of three “anomalies” discovered by it.

Verrimus said in a statement it could not comment specifically on the details of the job it did for the Garda watchdog in September 2013 but said it would "correct technical inaccuracies in reporting".

The British company said a mobile phone “cannot create a 3G base station, so it is impossible that Verrimus operator’s phones were the source of a fake Mobile Country Code”.

It added that any wifi device capable of audio, video or data gathering that sits on a secure internal wireless local area (WLAN) should not be attached and communicate with any device outside of its own secure network”.

An article in The Irish Independent claimed this morning that a wi-fi network in a nearby coffee shop was the source of one of the “anomalies” identified in the security audit at the GSOC offices.

The report also said “the detection of a UK 3G mobile network during a sweep came from the mobile phones being used by the Verrimus security experts themselves”.

A two-day Dáil debate on the alleged bugging gets underway later today.