The husband of Bertie Ahern’s former secretary has said he and his wife bought St Luke’s in Drumcondra because they were looking for a bigger family home and it was around the corner from where they lived.

Gráinne Carruth worked with Mr Ahern as his constituency secretary during the 1990s.

In a dramatic appearance as a witness in the Mahon tribunal in 2008, when it was investigating Mr Ahern’s personal finances, Ms Carruth admitted sterling amounts had been lodged to accounts associated with him. Mr Ahern had contended until then that he had never dealt in sterling currency.

It is believed Ms Carruth and her husband Eamonn O’Connell paid about €775,000 for St Luke’s, which was put on the market for €630,000. It is understood there were three bidders but Ms Carruth and Mr O’Connell were always the most active and made the clinching deal.

It is understood the couple, who have three children, had been looking for a larger family home in the area – they currently live very close to St Luke’s.

Yesterday Mr O'Connell said the former headquarters of Fianna Fáil in Dublin Central was "very convenient and handy" to where they live. "We have the same neighbours and it is just around the corner from where we live and my offices," he said.

By implication, the previous connection Ms Carruth had with the building, where she worked for a number of years, was a coincidence.

The building, which was owned by a local Fianna Fáil trust until 2012, was transferred back to Fianna Fáil’s central organisation three years ago.

The party put the house up for sale because it was no longer of use to the party and because the proceeds of the sale will add to the war chest of funds for the forthcoming general election.

In March 2008, Ms Carruth, under intense cross-examination, admitted to the tribunal that she lodged a sterling amount of £15,000 into accounts held by Mr Ahern and his two young daughters in 1994. She broke down in tears during the course of her testimoy.

The disclosure left the then taoiseach and leader of Fianna Fáil under enormous political pressure and he stepped down as head of government in early April 2008. Ms Carruth’s evidence was seen as a contributing factor.

In an interview at the time of his resignation, a clearly angry Mr Ahern branded the Mahon tribunal’s treatment of Ms Carruth as “appalling and low-life stuff”.

“There was no need to harangue her. She just didn’t remember something. She was concealing nothing. She was a mother-of-three . . . hauling her back on Holy Thursday, it was just low-life stuff,” he said.

Ms Carruth and her husband are understood to have required a larger family home. They live in a smaller house close to St Luke’s at present and have three children, aged between 12 and 15. Eamonn O’Connell’s accountancy practice is also located close by.