Mr Adams’s presence is so elevated these days that there is barely an important international event that occurs without the Sinn Fein president being asked to comment on it.

Where once his picture was taken in the company of masked men, these days he prefers to be photographed with American presidents, the Dalai Lama or even the Pope.

As sympathy for the victims of the atrocities that took place yesterday poured in, Mr Adams denounced the attacks as wrong and said that “those involved should stop”, apparently forgetting that his party has spent more than three decades fostering links with Eta, the group suspected of carrying out the bombings, and its political wing, Batasuna.

While republicans claim that there is much similarity between their struggle and the movement for an independent Basque country, the ties extend beyond the purely philosophical. During 30 years of violence, the two movements have forged deep links, to such an extent that a representative from Batasuna was inside Sinn Fein’s offices at Stormont before the 1998 Good Friday peace accord. It is no coincidence that Eta’s decision to call a ceasefire came less than six months after republicans signed up to a deal intended to end for good the conflict in Northern Ireland.

At the bottom of the Falls Road, in republican West Belfast, a mural boasts of the IRA’s links with resistance groups, including Eta.

For years a Batasuna representative has been welcomed at Sinn Fein’s Ard Fheis, its annual conference.

Links between the Provisional IRA, Sinn Fein’s military wing, and Eta were first established in the early 1970s, when the Basque terrorist group was at its most active. Small teams of IRA volunteers are believed to have travelled to northern Spain to forge an understanding with the group.

In the 1980s, Eta is believed to have provided logistical support to the IRA for some of its attacks on British interests on the Continent. More recently, Scotland Yard and Spanish police began an investigation into links between the two groups after Diarmuid O’Neill, an IRA suspect, was shot dead by police in Hammersmith, West London, in September 1996. The investigation started after a pro-Eta newspaper published a death notice for Mr O’Neill, said to have been a familiar face in the Basque country and whose girlfriend was from Bilbao.

Although in the post-September 11 world Sinn Fein is keen to play down its links with international terrorists, security sources have little doubt that they continue. Denis Donaldson, Sinn Fein’s head of administration at the Stormont assembly, who is awaiting trial in connection with an alleged IRA spy ring inside the Northern Ireland Office, was recently identified by police as one of the Provisionals’ “point men” with Eta during the worst years of the Troubles.