Charles Haughey used Royal Ulster Constabulary surveillance technology in political spying operations at the end of the 1970s, a new book on the undercover anti-terror war claims.

Haughey went on to boast that the use of the bugging equipment, which was meant for anti-terrorist operations in Northern Ireland, "changed the course of Irish political history". According to the book, Border Crossing, by George Clarke, a retired Special Branch officer, the future taoiseach even refused a request to hand back the two pieces of spying equipment.

Clarke says he lent the bugs – one in the shape of a pen, the other disguised as a 13-amp plug adapter, both of which he had bought in a specialist spy shop in London for £90 – to one of his counterparts in the Garda. They were passed at some point to a senior commander in the Garda in Dublin. Several months later, when Clarke asked for them back, his Garda contact confessed that the senior commander had told him that the bugs were now with Haughey, who would not hand them back.

Clarke, referring to his Garda contact and friend as "Garvin", recalled: "He [Garvin] told me that he had pressured his senior officer so much [for the return of the devices] that he asked him to visit him at Garda headquarters in Dublin. There, he was told that they had been passed to a politician who had requested bugging devices and he was refusing to return them. 'Garvin' was sworn to secrecy and told to claim expenses towards their cost."

Clarke said that when he had held a second meeting with "Garvin" in another attempt to get the bugs back, "Garvin" had named the politician as Haughey and recounted the conversation he had had with the senior Garda officer.

According to "Garvin", his senior commander had said: "I have known Charlie Haughey well for many years and when he asked me about bugging devices I couldn't refuse him. When I met him at a Fianna Fáil function a couple of weeks ago, we had a couple of minutes together alone and I asked him about the equipment I had loaned him… Haughey finished with: 'These gadgets have changed the course of Irish political history and taught me a lesson – that in life things are never as they seem. In politics, one must have a Machiavellian personality, it is crucial to know your friends'."

In the late 1970s, Haughey was rebuilding his reputation within Fianna Fáil after being sacked from the cabinet over the arms trials in 1970, when he and two other Fianna Fáil figures were accused of arming the nascent Provisional IRA. Haughey and his supporters were also plotting to overthrow taoiseach Jack Lynch, which they later achieved through an internal Fianna Fáil coup in 1979.

Haughey had a history of bugging political opponents and journalists he regarded as enemies: in 1982 he was exposed for ordering the bugging of the phones of three leading Irish journalists. There was no link, however, between the technology he used to do that and the RUC devices referred to by Clarke.