Exit, to the sound of corks and loud kisses, the divine Ms MacGregor

At exactly 9am yesterday on BBC Radio 4, Sue MacGregor finally hung up her headphones as co-presenter of the Today programme. In a rare slip of timing, she was defeated by the GMT bleeps as she struggled to remember the names of the show's producers – but then, she was drinking champagne at the time and the airwaves were briefly assaulted by a fusillade of noisy kisses and popping corks in the studio.

Her last words were, a little bathetically: "Thanks everyone. I'm off to a concert this evening. That's it from me. Our editors were, er, Victoria and Nick. Goodbye."

It's been 18 years since the MacGregor delivery – that intelligent, unflappable, gently probing, infuriatingly logical instrument – was first heard on Today, at 6am on 22 August 1984. Since then, it's "woken up the nation" (as Today presenters like to say) with news of the Berlin Wall, Tiananmen Square, the Gulf War, the fall of Thatcher, the release of Nelson Mandela and a couple of hundred other entries in the chronicle of modern history.

She has, in the process, entered public consciousness somewhere between a kindly-but-firm schoolmistress and an unattainable sex object. Like John Betjeman's tennis-playing goddess, Miss Joan Hunter Dunn, she enchants by simple means.

Across the nation, you could imagine otherwise sensible men wiping a moistened eye in valediction. No more would they tremble at her deliciously collusive suggestion: "Seventeen minutes to eight, let's take a look at the papers with Peter Donaldson." No more would they hear those sceptical mid-interview murmurs of "and you think that will make a difference, do you?".

No more will they quiver at her charmingly old-fashioned formulation, "ordinary citizens" – as in "How will this affect the ordinary citizens of this country?" No more could they hear her evident distaste when saying the word "crack" in a piece about the drugs trade. No longer would they envy someone called Roger Harrabin simply because of the way his name is caressed by her tongue in the words: "Roger Harrabin reports."

Until the end, Ms MacGregor was her flawlessly professional self on yesterday's programme, co-presenting with John Humphrys. She interviewed a scientist about government funding of stem-cell research, grilled a spin doctor from Consignia about the end of early mail deliveries (betraying a slight but audible exasperation at the inevitable Newspeak about "the customer coming first") and talked to Charles Kennedy about Stephen Byers's performance in the Commons.

She talked Zimbabwean elections and opium smuggling with the same cool aplomb. Around her, colleagues and contributors lightly joshed her. Gary Richardson, Today's waggish sports editor, selected two runners at Lingfield races in her honour, Most Saucy and Tunnel of Love – possibly references to the recent furore over Ms MacGregor's publication of frank revelations about her past amours. Roy Jenkins, in the "Thought for the Day" slot, mused what a "tremendous feat of endurance" it had been to preside over so many Thoughts for so long. John Humphrys got the time wrong – "because it's your last day".

Then, with 10 minutes to go, the programme launched into a sonic tribute to Ms MacGregor's finest moments and best rows. Among the latter was the electrifying interchange when Brian Mawhinney, the chairman of the Conservative Party under John Major, snarled at her (snarled! At Sue MacGregor!) for suggesting the Prime Minister might consider resigning. "Let's stay," he grated, "in the real world."

Celebrities sent taped messages of devotion – Neil Kinnock, Jack Cunningham (who used to be known as "minister for the Today programme"), Peter Hall, Michael Palin, Betty Boothroyd, Ann Widdecombe, Beryl Bainbridge, Andrew Motion, Simon Jenkins and the supreme boss, Greg Dyke.

Then Ms MacGregor's other Today colleague, James Naughtie, arrived with flowers, and Nick Clarke from The World at One turned up and what sounded like Lanson Black Label was poured out, and a brief impromptu party took over the studio. "I am not going to cry," said the divine Ms MacGregor – thrillingly contained to the last.