Remembrance is the price of grief, and the cost is hard to bear. Those afflicted by the aftermath of catastrophe wonder, rightly, why this year should be different from last year, and why they should be forced to relive horrors simply because fallible media memory has been prompted by a round, convenient, meaningless number on the calendars.

I make no excuses for the trade. Better that an enormity, in the proper sense, is remembered than forgotten when the thickets of ignorance and atrocity sprout by the day. Memory contains the hope, often forlorn, that something might be learned. Sometimes, intermittently, with luck, reporting fills the gaps.

I was in Omagh just after the bloody bomb, and then a year later, reluctantly. In the week of a promised eclipse of the sun I made a deal with my then-editor. I'll go back, I said, but there is one thing I won't do. I will not ask anyone the stupidest question in journalism: "How does it feel?"

I was in The Herald newsroom, a bit-player, on the night Pan Am Flight 103 fell on Lockerbie. I was back - still more reluctance - a decade ago. Sherwood Crescent; Rosebank Crescent; Dryfesdale Cemetery; the brooding silence at Tundergarth: in these honest, inconspicuous places the war on terror - selected, manipulated, the fount of a thousand lies - properly began. Poor Lockerbie.

The "anniversary piece", as we call it, rarely illuminates anything much. Prose becomes a little purplish and reverential, but that tends only to distress the bereaved further. They know what happened. They would rather know why it happened, and whether those responsible have been punished. Twenty years after Lockerbie, the truth - like Abdelbaset Ali Mohmed al Megrahi, the only man convicted of the mass murder of 270 people - remains locked away.

He didn't do it. If he was in any way involved he was neither the sole nor the principal actor. His country, Libya, is these days back in the oil-vending, terrorism-fighting fold. "Compensation" paid, it once again cuts Blair-brokered deals with the west. Syria, Iran, the CIA and geo-politics, US-style, have moved on. But the evidence against the man dying of stage-four prostate cancer in HM Prison Greenock remains flimsy, inconsistent, contradictory and deeply, as his lawyers might say, unsatisfactory.

This is not meant as another rehearsal of numerous theories. Suffice it to say that we have been told often enough by members of the American security apparatus - ask the bereaved Dr Jim Swire, if you doubt me - that the truth will not be made available. But here's the thing: if Lockerbie marked the real beginning of the terror war, long before 9/11, why are truth and facts still so dangerous? Why are those commodities always, persistently, as a matter of routine, withheld? Democracies depend, at minimum, on disclosure. Why did we wage war in Iraq? Why the war in Afghanistan? It is attested that these have been noble, necessary causes, essential in the struggle against dark, implacable forces. Perhaps. Bombings in London, Bali or Madrid were not fictions. The attack on Glasgow airport was no fantasy. So why does my government fight so hard to prevent me from reading the minutes of the Cabinet meetings during which the occupation of Iraq was discussed?

If the cause has been just, the truth is no threat. The "who" of Lockerbie or 9/11 never troubled me: hunt them down, I said, and still say. Even the lies over Iraq's mighty bio-chemical/nuclear WMD mirage could have been forgiven, just about, as errors, albeit persistent errors, in the heat of the moment.

You could almost - though I do not - recognise the deceits as the failings of flawed, panicking men who understood too little and said too much. But why have the deceits, like the wars, become self-perpetuating?

For several years Gordon Brown managed to avoid the appearance of complicity in the Iraq affair. As Chancellor, he knew all about the treasure expended, of course, but his public support for Tony Blair's adventure seemed no better than dutiful. In the weeks after the Downing Street tenancy changed hands, indeed, naive optimists liked to tell themselves that Gordon would be different. He would have no truck with Blair's legacy, he would distance himself from Bush, and Britain would be better for it.

When I was a child there was an artful con called the lucky bag. You bought your sticky tooth-rot, sight unseen, in the hope, always frustrated, that there might be something satisfying at the bottom of the poke. No chance, of course. But who knew that the guiding principles of the British state - ID cards, Lockerbie, Iraq, Afghanistan - would amount to little more than the cheapest rubbish from the corner shop?

We are done with Iraq: it's official. Opposition politicians have therefore demanded an inquiry into six years of inconclusive occupation. Mr Brown had led us to believe that a review of British successes would not be appropriate - a word to investigate - so long as we had troops on the ground. This week he told the Commons that the time is still not right.

The squaddies will be home by next summer. Of 4100 vestigial personnel, perhaps 400 will remain to help train Iraqi forces. The incoherent idea that no inquiry could take place while shots might be fired will be obviated, finally. But Downing Street insists still that the truth of the Iraq incursion cannot be examined while a single pair of British boots remains on the ground.

In historical terms, this is nonsense. Parliamentarians were asking hard questions about the Crimea botch long before Russia quit the field. Shell shortages in the First World War roused the Commons. Mr Brown tells us, meanwhile, that the Iraq incursion has succeeded in establishing democracy in that country. So surely an official inquiry would be a cause for celebration? The Prime Minister is not minded to grant that discussion. "It is something we will consider in the future," says No 10, lamely.

Mr Brown once said that an inquiry would be forthcoming when Iraq was "stabilised". He withdraws the last troops now because that stability is supposed to have been achieved. But even an inquiry behind closed doors of the sort conducted by Lord Franks in 1982, after the Falklands, is rejected. Why? A certain lack of pride in things done in Britain's name, perhaps? Or is the truth still proving a nuisance?

At a guess - and our letters page is always available, should he differ - Mr Blair did not hand over power without ensuring that inquiries, public or secret, were ruled out. If you count his various contradictory utterances over the past six years as testimony, after all, he might have some further explaining to do. He might even have to separate true from false, finally.

I despise conspiracy theories. They make life too easy for the powerful, who much prefer to dismiss every inconvenient truth as fantasy. But when 20 years elapse and the truth of the Lockerbie massacre remains contestable, when six bloody years go by with Iraq selected as the useful evil-of-the-month, the demand for truth is more than mere rhetoric.

It functions as a reminder, in fact, of the state we're in. We can call for facts, and insist on truth, and yet receive neither. We can whistle. In the dark.

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