Geoffrey Wheatcroft: Errol Flynn's part in Trimble's downfall

To compare our pious and wholesome Prime Minister with the most dissipated of all film stars might seem far-fetched, but in one way Tony Blair reminds me of Errol Flynn. When you look back over Mr Blair's career there is a consistent theme: the way those who have put their trust in him have unfailingly been disappointed, not to say betrayed.

Names almost at random include Sir Paddy Ashdown, who was all but promised a cabinet seat before the 1997 election, and Lord Jenkins of Hillhead, who thought Mr Blair was serious about electoral reform. Last January Mr Blair deserted Peter Mandelson, his most faithful lieutenant, for frankly frivolous reasons. And then there are those other dogged loyalists who still believe that Mr Blair will hold a referendum on the euro during this Parliament.

"You knew just where you were with Errol," a Hollywood friend of the libidinous swashbuckler once said. "He always let you down." In that respect, Tony Blair is the Errol Flynn of contemporary politics.

And yet of all those who have been let down by Mr Blair, none has more reason for bitterness than David Trimble. His resignation as First Minister a week ago left Northern Ireland in crisis (a condition the province knows well), and any confrontation today at the Garvaghy Road is unlikely to ease the atmosphere at tomorrow's all-party talks in Shropshire. But then nor is it likely that Mr Blair will examine his own responsibility for the latest impasse.

Republicans have rather successfully spun a line that decommissioning is a figment of Unionist imagination and was not originally considered a necessary part of the peace process. This is simply untrue, as can be seen in tonight's penultimate episode of Endgame in Ireland on BBC2, the latest of Norma Percy's outstanding documentary series. Here is the contemporary evidence that what Sir Patrick Mayhew called "the actual decommissioning of some arms as a tangible confidence-building measure" was repeatedly required of the IRA.

Last week The Guardian called decommissioning a red herring. But in 1995 two of that paper's own correspondents wrote: "What is not in doubt is that prior to and immediately following the IRA ceasefire the political parties in the Irish republic shared London's view that guns would have to be handed over before substantive talks got under way." Quite so: in 1993, Dick Spring as deputy prime minister told the Dublin parliament: "We are talking about a handing up of arms. There can be no equivocation."

We are now told that any demand for disarming was always absurd. Or as Kevin Toolis writes: "There is not going to be any IRA decommissioning of weapons this side of a united Ireland. Not one bullet, one gun. Full stop. Final." All I would say to that is that in May 1998 I covered the referendum campaign on the Belfast Agreement, and if what Mr Toolis says had been spelled out then in those terms, the referendum in Northern Ireland would not have passed. Full stop.

What mattered to Mr Trimble was less what was said by Dublin politicians or republican apologists than what was said by Tony Blair. He not only personally told the Ulster voters that "prisoners will be kept in unless violence is given up for good", but he privately assured Mr Trimble that there would be some measure of IRA disarmament before the formation of an Ulster executive.

It may be genuinely difficult for a man with Mr Blair's own tenuous hold on truth to understand that others think he might mean what he says. But he could at least try to see that, by doing what he did to Mr Trimble, he left him – in a hallowed phrase of Irish politics – with his arse hanging out of the window.

Whatever happens to him – whether he somehow comes back to office, or returns to academic law, or joins the British shadow cabinet, as has been quaintly suggested – he remains one of the most interesting politicians of the age. Alan Watkins once wrote that he was the most capable party leader at Westminster. More fascinating than Mr Trimble's latest manoeuvrings is his much longer political evolution, something for which he has not been given enough credit. The Orange extremist of the 1970s became the Nobel prize-winner who could acknowledge in his acceptance speech that Northern Ireland had been "a cold house for Catholics".

Even when he had disavowed the wilder shores of loyalism, Mr Trimble long remained less a "Unionist" in a literal sense than an Ulster nationalist. This is something quite misunderstood in England. Twenty years ago found David Trimble actually advocating an independent Ulster. Now he has moved well away from that position also, and wants to find a way "of involving the province much more in British political life". This change itself suggests a certain detachment on his part from his Ulster Unionist Party, or perhaps disenchantment with provincial politics, and the devolved government which was for so long his obsessive goal.

Nor would that be odd. The latest result of what John Bruton, the last Irish prime minister, wearily used to call "the f------ peace process" has been the squeezing out of the centre parties. Sinn Fein overtook the SDLP at the general election, and the Democratic Unionists are rapidly overtaking the UUP. In London dismay and astonishment are expressed at this, but nothing could be more predictable. Nationalist voters turn from the SDLP to Sinn Fein on the principle, why vote for the monkey when you can vote for the organ-grinder?

And Unionists – those grim, unloved, literal-minded protestants – abandon the man who was abandoned by Tony Blair when he gave promises he had no intention of keeping. Will Errol Blair ever see that there are some circumstances in which letting others down can have deadly serious consequences?