Tony Blair predicted that referendums on the 1998 Good Friday Agreement would end the international perceptions that violence in Northern Ireland “had some justification”.

The former prime minister’s remarks were made in a meeting with Orange Order leaders.

He also said that past British government attempts to tackle violence in Northern Ireland had been hindered by the perception internationally that “Sinn Fein somehow had a respectable case”.

Details of the meeting are contained in documents held at the Public Record Office in Belfast. Hundreds of the files are now being opened for public viewing under the 30/20-year rule.

The Orange Order leadership had sought a meeting with Mr Blair following the signing of the historic peace agreement, but before the public on both sides of the Irish border had voted in a referendum on the political deal.

The prime minister said that past British governments had been hindered by the perception in some minds, not least internationally, that Sinn Fein somehow had a respectable case and that violence somehow had some justification

Papers reveal that the order had been offered meetings with the then-secretary of state Mo Mowlam and Northern Ireland Office (NIO) ministers, but had held out for a face-to-face meeting with Mr Blair to express their concerns over the agreement.

Mr Blair’s parliamentary private secretary John Holmes recorded the content of the meeting in a letter sent to the NIO on May 7 1998.

It states that the prime minister met with Orange leaders Robert Saulters, John McCrae, Denis Watson, George Patten and Michael Bishop.

The letter states: “Bishop said that British governments had not in the past showed any resolve to tackle violence seriously. Why should it be different in the future?

“The prime minister said that past British governments had been hindered by the perception in some minds, not least internationally, that Sinn Fein somehow had a respectable case and that violence somehow had some justification.

“But once the referendums were through, violence could have no respectability left anywhere. That was also the US view.

“That was why it was important to get the agreement through, not least because it enshrined the principle of consent.”

The letter also records the Orange leaders expressing concern over cross-community voting procedures in the proposed new Stormont Assembly.

It states: “The prime minister said that without some form of cross-community provision, the agreement would fall to pieces.

“If there was a simple majority system only, and the nationalists felt it was being abused, the Assembly would collapse.

“At the end of the day the agreement would only work if people wanted to work together.

“But where there were sensitive issues at stake, cross-community decisions were undoubtedly needed.”

The letter goes on to state that the Orange leaders raised concerns about referendums on Irish unity being included in the agreement.

It states: “Watson asked about the referendums on a united Ireland provided for in the agreement.

“Was the decision on this solely for the British government, or would the Irish government or the north/south council have a role?

“People feared that in 30 years’ time, the nationalists might have the majority and insist on using it.

“The prime minister said that the seven-year interval between referendums was supposed to reassure people that this was a minimum gap.

“We had no plans to hold a referendum at all and there was certainly no requirement to hold one every seven years.

“Dr (Mo) Mowlam added that the situation in 2025 ought to look very different.

“Moreover, the polls showed that 10-15% of the Nationalist community wanted the Union preserved.”

The Orange leaders also raised concerns over the release of paramilitary prisoners, but Mr Blair said this was the best way of avoiding further violence.