DUP leader Ian Paisley accused Secretary of State Tom King of treason
Ian Paisley branded the Irish foreign minister "a parasite" in a furious letter attacking the Anglo-Irish Agreement.
He described Peter Barry, a future Tanaiste, as an impostor and "the lowest form of political existence".
The letter, signed "yours contemptuously" by Mr Paisley and Ulster Unionist MP Harold McCusker, was hand-delivered to Secretary of State Tom King's office on December 11, 1985, to coincide with the first meeting of the Anglo-Irish Intergovernmental Conference, a cross-border body set up as part of the Agreement.
It stated: "Sir, once again, to your shame, you are engaged in treachery against Ulster and its constitutional integrity. In the name of the Unionist majority, whose rights you have trampled in the gutter, we repudiate you."