What should we call three poets seated together on a stage?

A dithyramb of poets, perhaps, for each appearing here was a laureate in one way or another. To their right, a man stood with sweet-sounding pipes of Pan which fanfared each reading at the lectern. In an Aye Write! festival of record ticket sales, Carol Ann Duffy, Gillian Clarke and Liz Lochhead were performing to a packed house at the Mitchell Library in Glasgow, John Sampson accompanying their words with music that set the audience humming.

This bardic evening began on a keening note. Duffy, the Poet Laureate, reminded us how poetry can capture a present week of terror when yet more lives were shattered in the wake of war: 16 Afghans, nine of them children, murdered by an American soldier on a killing spree; six British soldiers torn apart in Helmand when their armoured vehicle proved no shield against a Taliban bomb. "If poetry could tell it backwards, true, begin/ that moment shrapnel scythed you to the stinking mud-/ If poetry could truly write it backwards,/ then it would". Duffy wrote those lines in commemoration of Harry Patch, the last surviving British soldier from the First World War. As she read the lines amid the week's raw conflicts, her audience was transfixed.

Tragedy, piercing, but never mawkish, ran through poems by Gillian Clarke, the National Poet of Wales. But here was warm, joyful humanity, as in Clarke's memories of being a teenage convent border, "restless for life to begin", reading of "Heathcliff, in bed after lights out". Scotland's Makar, Liz Lochhead, spoke of the love/hate relationship between poets and words when writing to order. She then demonstrated her genius at that challenge by reading her commissioned poem for Westminster Abbey's recent Commonwealth Day celebrations. Not only was the Queen in the front pew, but Lochhead had to follow Rufus Wainwright singing Leonard Cohen's potent Hallelujah.

The festival's final weekend presented two political star turns: Tam Dalyell and Alistair Darling each addressed sell-out sessions on their respective memoirs, The Importance of Being Awkward, and Back from the Brink. If it's possible for the lugubrious to be engaging Dalyell knows the trick. To loud applause he described himself as a Boy Scout goodie, reckless with a streak of honesty which did nothing to equip him for ministerial office. And, his face artfully melancholic in repose, he insisted there was nothing more ex than an ex MP.

Alistair Darling, Labour Chancellor when money melt-down went global, said nobody "clocked" the deep fractures in world banking before 2008. When, in that year, he offered a warning, cross-party anger damned him "irresponsible". With no desire now to return to front-line politics, Darling confirmed he would play a full role in opposing the independence referendum nearer to 2014.

Tom Devine's festival tour de force centred on Scotland's global diaspora, the subject of the historian's latest book, To the Ends of the Earth. Since the 18th century particularly, Scots, he said, had a culture of mobility and opportunistic emigration. Unlike impoverished exiles, they landed abroad with "the very strong Scottish brand" of better literacy rates and physical skills than elsewhere in Europe.

Andrew O'Hagan, novelist (The Missing) and essayist (The Atlantic Ocean), also inhabited mobility with relish. He told a packed audience that public libraries and books had set him free to find or invent who he was. To those who claimed Scottish writers lost their strong Scottish voice when they moved away, he said they simply took its language and rhythms to somewhere else. For him, Glasgow was a moveable feast, its dust forever carried on his shoes.