Former British prime minister Sir John Major has hailed the document he agreed with Albert Reynolds in 1993 which prepared the ground for the IRA ceasefire the following year and cemented a new, closer relationship between London and Dublin.

Speaking in Dublin at the invitation of Tánaiste Eamon Gilmore at an event to mark the 20th anniversary of the Downing Street Declaration last night, Sir John said it "set out the principles that both the British and Irish governments were agreed upon".

Its effect was to put pressure “on the violent fringes in both the unionist and nationalist communities”, he said.

He insisted that the nascent peace process had no one single hero. Rather it took foresight and considerable bravery of a great many people including those who risked their lives.

The declaration “boxed in” those in paramilitary organisations. “In the eyes of their former supporters they were no longer seen as fighters for a political cause but, instead, as a barrier to peace, responsible for so much misery, so many deaths – often of innocent bystanders.”

Mr Major cited the many bombing atrocities around that time, including the Shankill bombing and the Warrington attack in which two young boys lost their lives.

He said that bombing was the single greatest moment of difficulty from his perspective throughout the peace process. However, he said it was vital to proceed despite the pressure from his own backbenchers in Westminster to call off all dealings with the Irish.

Mr Major did not mention his predecessor Mrs Thatcher by name, but he voiced indirect criticisms of her through his insistence that previous policy would not have led to peace.

Albert Reynolds was unable to attend the event at Iveagh House, but his wife, Kathleen and three daughters were present. Also there were former tánaiste Dick Spring, government negotiator Martin Mansergh and former US senator George Mitchell who chaired the talks which concluded the Belfast Agreement.