The close relationship between Bertie Ahern and Tony Blair was fundamental to the success of the Belfast Agreement and the peace process, former British government spokesman Alastair Campbell said last night.

He was speaking at the launch of the latest volume of his diaries by former taoiseach Mr Ahern at a reception in the Ely Gallery in Dublin. Mr Ahern also wrote one of two forewords to the book entitled The Irish Diaries, 1994 to 2003. The other was written by Mr Blair.

The book traces in diary form the involvement of Mr Blair and the British government in the tortuous negotiations that led up to the signing of the Belfast Agreement in April 1998.

At the launch, Mr Campbell focused on the close friendship between the leaders. “Bertie was so fundamentally involved. His partnership with Tony was so fundamental to the whole thing,” he said.

Mr Campbell said the other key personality in the whole process was Jonathan Powell, Mr Blair's chief of staff during his period in office.

A former journalist and inveterate diarist (Mr Campbell has already published five volumes) he conceded that the immediacy of the diaries ran the "risk of being deeply unfair" to former Ulster Unionist leader David Trimble. The complex difficulties faced by Mr Trimble explained how he might have presented at the time.

In contrast, he praised Mr Ahern as “having an incredible capacity to absorb things”.

Vital relationship
He said the other vital relationship was the extraordinarily strong one with the US president Bill Clinton. The political friendship allowed Mr Blair and Mr Clinton to have "a straightforward, honest conversation that can lead to a decision that is very important".

Of Mr Blair and Mr Ahern, he said: “It really mattered that they got on.”

Mr Campbell said he could not think of a taoiseach and prime minister who enjoyed a better relationship.

He said of the agreement brokered on that snowy Good Friday: “When it came together, to this day I cannot explain that. It just so happened that at a certain point of time they came together [having travelled from] so many directions and it worked.”

Mr Ahern, who did not address the audience last night, wrote in the foreword about the closeness of the relationship.

“I spent weekends with Tony and his family at Chequers when we were in office. I was in and out of Downing Street and he came to see me in Drumcondra and met my friends.

“I believe this friendship . . . was crucial in building an entirely new relationship between our countries,” he wrote.