Band Aid at 40: Bob Geldof recalls the iconic charity single's chaotic creation

Forty years later, Geldof admits his second career might never have started had the first not foundered so badly. Their 1984 album had not troubled the chart. At the close of a gloomy October day spent trying unsuccessfully to interest anyone in their new single and, "thinking the best part of my life might be over", he slunk home early to his girlfriend Paula Yates and their young child.

"That's how I saw Michael Buerk's report about the Ethiopian famine on the six o'clock news," he explains. "Le Bon and Boy George and Bono and the rest of them would have been out being rock stars. I wasn't. I was on my sofa."

Galvanised by what he saw, he conceived the idea of a fund-raising single, plundering the family's phone book for top pop names to sing on it. "Although they had pushed our lot aside, I knew all these people through Paula and The Tube [the Channel 4 music show she presented]. I’ve got Polaroids of people like Simon Le Bon at my place, asleep on the sitting room floor because they were just exhausted."

The song Do They Know It's Christmas? was arrived at by putting together a pre-existing Midge Ure composition with a fragment of a song Geldof had failed to interest the Rats in. "Midge sent me the tune and I said, 'Dude, that's f**king Z Cars.' He said, 'Better than anything you can write.' Midge will grudgingly admit there may also be an element of The Dam Busters there."

It proved serviceable. A new BBC documentary of how it came to be recorded, put together from footage shot on the day that has lain in a vault ever since, begins with Geldof and Ure waiting like nervous party hosts to see who turns up first. "Midge said to me, 'Who's coming?' I said, 'Oh, everyone,' but still I wasn't sure. I didn't think Spandau would come back from Japan. Why would you?"

By the time I arrived that day, Sting, Paul Weller and Spandau Ballet were already there. By mid-morning, the faces were rolling in so freely that you stopped taking note. Boy George made his big entrance in the evening, having flown in from New York on Concorde. Such were the times.

Four years earlier, most of the oiks in that room wouldn't have been able to scrape the price of a cab; now here they were in front of the cameras, savouring their moment, doing their bit, feeling their juice, not entirely sure where they were. Geldof can’t be sure of the name of the bewildered band member who recorded a message apologising to "all our Ethiopian fans" for not being able to tour there, so he must remain the day's Unknown Soldier.

The pop historian in Geldof is captivated by the film, likening it to the Maysles brothers' famous footage of the Beatles arriving in New York in 1964.

"There's no filter. What I love about it is the contrast with We Are the World [the US equivalent recorded the following year]. There you have these giants, people like Ray Charles, Tina Turner and Willie Nelson, but back in the UK there are these spotty kids just out of school. They’re charming, guileless, innocent almost. They’re rivals for sure, but they're laughing and carrying on.

"Then you have a previous generation, like me and Weller and Midge trying to keep it together. Everyone crowds into the studio control room, which is the very opposite of Quincy Jones, let me assure you. It's wonderful, it’s moving and no one in that room, me included, had a clue what was coming next."

There are aspects of the day Geldof has forgotten or didn't notice back then. Paul Weller, at the time in his Style Council phase, arrived sporting a walking stick. "I imagined he and I hadn’t got along, but in the film I can see him sitting behind Midge, chipping in."

He's forgotten that he phoned Frankie Goes to Hollywood, who were overseas, to beg even the tiniest contribution from the year’s hot property. The sequence where he's heard introducing a visibly nervous Bono ("He wasn't sure U2 should be there at all, and he was iffy about Le Bon's bouffant") to a clearly shy George Michael (who says, "I get nervous around pop stars," before transforming his vocal line with an artful tweak) has a touch of Stella Street. "It's mad in retrospect. Two years later these people were the determinants of pop music all over the world."

The world outside the window of Sarm Studios remains distinctly 1984. Holland Park looks shabby, the reporters use notepads, people smoke, calls are made on rotary dial phones and nobody asks why the chorus contains only four women. "It has to be seen in the context of its times," he says. "You don't get Band Aid without Loadsamoney [Harry Enfield's '80s comedy character]." The soloists line up to record their lines in front of each other. These are done "dry", meaning nobody else can hear the track they’re singing to. Under such conditions, even Pavarotti would sound like a drunk.

"It was like school. ‘Who’s going first?’ ‘Not me, f**k off.’ Midge was like the kindly teacher and I was there tapping my fingers impatiently. Anyway, Paul Young stepped up and volunteered to do the first line."

Bob is seen reminding them what they’re singing about. “Bono took me aside and asked if I was sure I wanted him to sing this line about ‘Tonight, thank God it’s them instead of you.’ I was able to say, this is not soggy liberalism; this is coded anger, like Michael Buerk’s report. And because he’s got a voice from God and he can absorb the sense of a song like few others, he nailed it.”

In time, Bono's bravura delivery of that zinger attracted a fan club. When, on its 20th anniversary, a subsequent generation of pop stars gathered to record the song, both Robbie Williams and Justin Hawkins tried to bag the line for themselves. "They were still arguing when the door swings open and in walks Bono, who says, 'Are we doing my line yet?' He came back and sang it again in 2014, when we were doing it for the Ebola crisis."

What the film can't capture is the behind-the-scenes arm wrestling of the week between completion and release, during the course of which Geldof learnt to go to the top. "I did a deal with the Daily Mirror by calling [owner] Robert Maxwell. The old shyster rang me at 3am, saying he was going to charge for the poster of the Band Aid line-up. I told him he couldn’t. When Top of the Pops said they couldn’t play the record because it wasn’t yet in the charts, I went to [BBC1 controller] Michael Grade. He said, 'Why don't I give you five minutes before Top of the Pops? Can you get someone to introduce it?’ I said, ‘I could f**king do that,’ and he said, 'Mmm, perhaps somebody else, Bob.'" Anyway, David Bowie did it. I asked him to wear my Feed the World T-shirt, which was based on Katharine Hamnett's [designer T-shirts]. Of course, it looked s**t on me and brilliant on him.

"I was having difficulty getting the Musicians' Union to sign off on all these people being present. I'd come to the end of my tether. The only way to get it to Radio 1 was to leave the MU and start our own union. If we started the Pop Music Union, left the MU and said to the BBC, 'You can play none of these artists' records without the PMU’s consent,’ it would have meant that Radio 1 would have come off air. I understood the power that was in that room." The union settled; the Geldof MO was established.

As we wind up, I remind him that 40 years earlier, I had asked if this would be the end of his involvement with charity – he said yes. He laughs. His morning has begun, as most days do, with 10 emails of Band Aid Trust-related matters. "But if you asked me again today, the answer would be the same."

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