A senior ex-Provisional IRA figure has spoken of his disillusionment with the failure of the peace process to progress towards Irish unity and has urged nationalists not to pass information onto the PSNI.

In an exclusive interview with the Sunday Tribune, Brian Arthurs (45), a former commander of the Tyrone Brigade, said the political settlement in the north wasn't what republicans had fought for.

Arthurs, once a close associate of Gerry Adams and Martin McGuinness, disclosed he had left Sinn Féin two years ago after a major split in the republican movement in Tyrone. Five Sinn Féin cumainn, and 90% of the East Tyrone brigade left in the previously unreported move.

Arthurs said: "No one can deny there have been changes in the north but it is an equality agenda being pursued. People did not die, they did not take up arms, for equality. They did so for Irish freedom. Yet a huge £100m MI5 building has been built in the north and 5,000 British soldiers remain here.

"David Cameron told the Tory party conference that he was prime minister of Britain and Northern Ireland. He stressed the importance of the union. Republicans cannot see Irish unity in any of this. It should be remembered that, as republicans, we were committed to fight on until Britain made a declaration of intent to withdraw from Ireland."

Similar sentiments were voiced by Peter McCaughey (40), another senior ex-Provisional IRA member from Tyrone, who left Sinn Féin with Arthurs. Both men come from prominent republican families.

Arthurs' brother Declan was one of eight IRA members shot dead by the SAS in Loughall in 1987. McCaughey's brother Martin was killed by the SAS in 1990.

Six independent republican societies with around 200 members have now been formed in Tyrone. Another six are being set up. They include new young members and veteran republicans.

Peter McCaughey said he was "extremely disappointed" with Sinn Féin's condemnation of those still involved in 'armed struggle'. Martin McGuinness recently called Real IRA bombers in Derry "conflict junkies and Neanderthals". He condemned the gunmen who killed two British soldiers at Massereene as "traitors to the island of Ireland".

Peter McCaughey said: "Was my brother a 'conflict junkie', 'a Neanderthal' or a 'traitor to the island of Ireland'? That is what is what Martin McGuinness would call him if he was killed on active service today. My brother was a freedom fighter. He fought for a united Ireland. That goal is still there and remains deeply cherished by republicans in Tyrone.

"We were disgusted when Martin McGuinness stood at the gates of Stormont with the Chief Constable of the PSNI after Massereene and demonised republicans. He did not speak for us."

Brian Arthurs said nationalists shouldn't heed calls from Sinn Féin and the SDLP to pass information to the PSNI because it would inevitably lead to the "imprisonment or death" of republicans.