Singing Bob Dylan's praises – the Brothers and Sisters of LA

Talking to Merry Clayton is such an uplifting experience it should be prescribed on the NHS. The 65-year-old from New Orleans had the quintessential soul singer's upbringing – preacher's daughter, raised to sing gospel – and she speaks with the soaring cadences of the pulpit, radiant with enthusiasm. Some might say she's a formidably talented backing singer (Ray Charles, Carole King, Neil Young and, most famously, the Rolling Stones' Gimme Shelter) who never found the recognition and solo success she deserved. She would counter that she has sung professionally for half a century and "there was always something wonderful".

The past year has been particularly wonderful, with a key role in the Oscar-winning documentary 20 Feet From Stardom, her first ever best-of album and more press coverage than she's ever had in her life. Now the Seattle label Light in the Attic is reissuing Dylan's Gospel, a 1969 album recorded by a dream team of backing singers known as the Brothers and Sisters of LA. Her reaction down the phone is like a gale of good vibes blowing in from the Atlantic. "It's so fabulous, so timely, so wonderful."

The reissue is long overdue. Conceived by record producer Lou Adler, who admired backing singers so much that he sometimes paid them triple scale, it features 27 vocalists, including Clayton, Clydie King, Patrice Holloway, Gloria Jones and Edna Wright, injecting the likes of Chimes of Freedom and Lay Lady Lay with Baptist gusto. It's a righteous, inspiring, beautiful piece of work.

In 1969, Adler had already found success with the Mamas & the Papas, Dunhill Records and the Monterey pop festival. Soon he would strike gold with Carole King's Tapestry, at one point the biggest-selling album ever, before swapping music for movie production with Cheech & Chong and The Rocky Horror Picture Show. Now 80, he can't remember exactly how he came up with Dylan's Gospel ("I wish I had that kind of memory left") but he saw a fruitful connection between "the spiritual feeling to [Dylan's] lyrics below the surface" and the Southern Baptist upbringing of his favourite backing singers.

Arranger Gene Page, best known for his later work with Barry White and several Motown stars, called up 20-year-old Merry Clayton, who quickly became Adler's close friend and collaborator. "I liked her personality and confidence," Adler says. "If there was a lifting force among all those singers, it was Merry Clayton."

"I call him Uncle Lou," Clayton says. "He's so cool and so kind but he knows exactly what he wants and exactly how to get it out of you. He's a fantastic producer and a splendiferous man. I don't do anything without conferring with Lou, still to this day."

Clayton was particularly thrilled to be singing lead on The Times They Are A-Changin'. "I'd met Bob during that period and I just adored him. I loved what he was saying." She recites the first verse in a tone of wonder. "It was an honour to sing that. We had the Vietnam war and a big racial situation so that spoke to my heart. My father was part of the civil rights movement with Dr King. I wasn't going to stand on the frontlines like my father and mother but my protest was given through the music."

Every word of her version is wrenching and magnificent. You can hear the same intensity in her volcanic 1971 version of Neil Young's Southern Man and in her transformative, apocalyptic performance on Gimme Shelter. When the pregnant singer was summoned, at the last minute, to join the Stones one night in autumn 1969, she was in her pink silk pyjamas and simply threw on a mink coat for the session.

"I really don't want to go to this session because it's 11.30 at night," she says, warming to the anecdote. "I refuse to get dressed. At the studio I'm reading over the lyric and I'm saying, Rape? Murder? Honey what does this mean? They gave me the gist of it. I just interpreted it the way I felt it. At that time we really did need shelter. Rape, murder was absolutely just a shot away."

Clayton's faith in the political messages her voice could convey to listeners was so immense that in 1974 she sang on Lynyrd Skynyrd's controversial Sweet Home Alabama, a song she actively disagreed with. Approached by fellow backing singer Clydie King, she agreed on one condition.

"I said we're going to sing the crap out of this song. They have the nerve to sing Sweet Home Alabama! That's the white interpretation of Alabama. It's not sweet home to black people! It's not sweet home at all. We're going to sing it like a protest song. We were singing it through our teeth, like we were really angry: We're going to sing your song, honey, but not because we want to – because it's necessary."

The invitation from King was typical. Although backing singers were technically competing for work, Clayton talks of a "sisterhood" of allies who helped each other get jobs. "I don't think it was competitive in any way," confirms Adler. "It was an unofficial union. They didn't have formal representation. They took care of each other."

So the Dylan's Gospel sessions in June 1969 were something of a love-in. Adler and Page arranged the seats in Hollywood's Sound Recorders Studios to resemble church pews, laid on ample refreshments and invited A-list friends such as Carole King and John Phillips to drop in.

"Everyone was off doing different things at that time, so for Lou to bring us all together in one session was just the best," Clayton says. "Between songs we'd hang out and then Gene Page's sister Sylvia would blow her whistle and we'd get back into shape. When we finished, Lou bought a case of champagne and we'd sit down and drink and talk and have dessert and listen to the record. It was the fellowship, that's what I loved."

Unfortunately, Dylan's Gospel came out just as Adler's Ode Records was changing distributor so it fell through the cracks despite warm reviews. Even more disappointing to him was the fate of the excellent solo albums he produced for Clayton in the early 70s.

"Some backing singers might have the voice but they don't have the charisma, the drive, the stage presence," he says. "Merry had them all. We tried. Maybe there was only room on Top 40 radio for one Aretha Franklin at that time. That's the only thing I can come up with. Because she had everything that should have made her a star."

Clayton, however, says she came to terms with her near miss years ago. "I really didn't have any time to worry about what didn't make it. I was always busy. You do the best you can with what you've got and you just keep moving forward."

And what did Dylan make of his gospel makeover? Adler can't say because, surprisingly, they've never met, despite having many mutual friends. "What's ironic is that we both have 12-year-olds who hang out together," he says. "The other night I was going over to Bob Dylan's house to pick up my son but I still didn't see him. So I've never known his reaction."

If Dylan has any sense he should love it. It's hard not to.