'When Bob first came into my office to discuss it, I thought he was joking', remembers promoter Harvey Goldsmith.
'In 1985 there weren't fax machines, let alone computers, mobile phones or anything else. We were working on telex and landlines. I remember sitting in my office with a big satellite map and a pair of old callipers, trying to map out where the satellite was going to be at certain times.
'Once the BBC had committed, we used that as leverage to persuade broadcasters all over the world to do it... the first time that had ever happened. It was my job to pick up the pieces and make it work.'
Said Francis Rossi of Status Quo, 'this was the dickheads in rock'n'roll, just getting on with it.'
It was an understatement. Not even those involved were prepared for how things would pan out on the day.
No one was ready ... except Queen,' recalls Pete Smith, the show's worldwide event coordinator, and author of 'Live Aid.'
'I saw the set on the monitors backstage. Queen tore up the rule book and rewrote it in twenty minutes flat. The effect was palpable. Live Aid was now cooking on gas.'
At their best both musically and technically - there was no more professional rock band in existence at that point (and probably still isn't) - Queen's reputation on the world stage was confoundedly on the wane. Their popularity had slipped due to a plethora of miscalculations, mishaps, and a general, sweeping change in musical tastes. Queen were beginning to feel that they'd had their day. A permanent split was on the cards. They'd discussed it. Thanks to Live Aid, all this was about to change.
Backstage, as the band awaited their turn,
'Freddie sat holding court, in that perfectly camp but quite humble way of his', remembers publicist Bernard Doherty.
'He knew the power he had over people, but it didn't go to his head. If he'd been sitting outside a beach hut in Southend-on-Sea, he'd have taken people's breath away. He was a true star, with that indefinable quality.
'And they went out there and won. What else do we remember about Live Aid? The sound going down on The Who. Bono getting in the zone, losing the plot, breaking the rules of performance. Simon le Bon, with the bum note of all time. The critics drooling over Bowie. Phil Collins playing both Wembley and JFK, courtesy of Concorde. As for Queen, they did exactly what Bob had asked them to. I watched from the wings and I was blown away.'
Some of us did. All of us were. It was Queen who stole the show. They drew from every influence, every which way. So many other supreme performers sprang back into my mind at that point: Alex Harvey, the great glam rocker of the Sensational Alex Harvey Band. Ian Dury and The Blockheads. Mick Jagger. Ziggy Stardust and the Spiders. What Freddie displayed better than on perhaps any other occasion was instinctive star quality, as well as a phenomenal grasp of what makes a must-watch show. He conjured all the genius of Vaudeville. The ultimate peacock, Freddie seduced us all.
'Who came on before of after Queen?' Doherty points out.
'Hardly anyone remembers. What do I remember? That Freddie Mercury was the greatest performer on the day. Perhaps the greatest performer ever.'
The other members of Queen were the first to praise their own frontman.
'The rest of us played ok, but Freddie was out there and took it to another level,' said Brian May, with typical modesty.
'It wasn't just Queen fans. He connected with everyone.
'Live Aid WAS Freddie. He was unique. You could almost see our music flowing through him. You couldn't ignore him. He was original. Special. It wasn't just our fans we were playing to, it was everyone's fans. Freddie really gave it his all,'
Of all Queen's 704 live performances fronted by Freddie Mercury, it remains their most iconic, their finest hour. Live Aid gave the band the perfect opportunity to demonstrate that, stripped of props and trappings, of their own lighting rig and sound equipment, of fog and smoke and other special effects, without even the natural magic of dusk and with fewer than 20 minutes in which to prove themselves, they were unchallenged sovereigns who still had what it took to rock the world.
Bravo Adam Lambert: your efforts in London this week have been flawless. You've gone the distance, and some. It takes courage to front a band as brilliant as Queen when you know that even your best gut-busting effort can never be as good.
To the tearful clown who had the last laugh, then ... and to Brian May and Roger Taylor, keeping on to the end of the road. They'll die with their boots on, those two. They will do so in Freddie's memory. Good on them.
Freddie Mercury: The Definitive Biography (C) 2012
Hodder & Stoughton UK, and available from this week through Touchstone Books/Simon & Schuster across the USA, wherever books are sold.