Here are excerpts from the interviews:

"They were actually very comfortable, very easy to wear," Benny Andersson says of Abba’s flamboyant silver and glitter stage shoes.

But presumably it was easier for Andersson sitting down behind the piano instead of teetering like his band mates?

"No, no, no, I mean they were really comfortable. I wore them around the house for three or four years."

"I got them in London, with blue snake skin squares."

Andersson and fellow Abba songwriter Bjorn Ulvaeus are back in London for the 10th anniversary of Mamma Mia! – the world-conquering musical, based round some of their best-known tunes.

Since its world premiere in the West End on 6 April 1999, the stage show has been seen by 32 million people in 190 cities around the world and has been performed in nine different languages.

Last summer’s smash hit film version, starring Meryl Streep, has already made more than £400m.

Andersson and Ulvaeus are on relaxed and charming form as they remember how they wrote some of the hits featured in the show.

"It would always start with a piano and a guitar and mumbling in a nonsense language we’d make up – half-English, half-Swedish, a bit French," says Andersson.

Bjorn Ulvaeus: "You never knew where you’d end up.

"So, we’d start maybe playing a good song like Sloop John B [by the Beach Boys] and you’d come out of it into something quite different like Thank You for the Music."

They say they can’t remember how Dancing Queen – a number one hit single all over the world in 1976 and 1977 and a feel good highlight of the show and film – came about.

"I don’t remember," says Ulvaeus.

"We’d meet at 10am, stop at 5pm.

"That’s the way to get rid of the garbage – you work it through."

Lyricist Ulvaeus says his words were written last of all.

"The words might come from a single image, a glimpse of something. We don’t know how it works – it’s a miracle. And I like that."

Abba never formally broke up.

The pair talk of "deciding to take a break" in 1982 – a break which they still seem to be on.

Which is just one reason why they’re plagued with their least favourite question from journalists and fans. Will Andersson, Ulvaeus, Agnetha Faltskog and Anni-Frid Lyngstad get together again?

It’s obvious they don’t need the fame or the money but wouldn’t it be fun?

"No," they both reply.

"Why would you do the same again?" adds Andersson. "It would take you nowhere."

They say no amount of money would tempt them and have reportedly turned down a staggering $1bn (£683m) to tour.

"I see myself walking on stage, as ABBA, and an audience being disappointed because it wasn’t what they anticipated," Ulvaeus says.

"They’d want the old energy, the old youthfulness. Why disappoint them? Why disappoint myself? There’s absolutely no reason to do that."

Instead the duo are busy with musicals, which Andersson says take "more than just a three-minute song".

They had a big hit in their home country of Sweden, with Kristina fran Duvemala, a big orchestral production about emigration and poverty, based on the work of Swedish novelist Vilhelm Moberg.   

They’re preparing for performances in English in New York in September.

"It would be nicer to do something new, with the same team, but new story, new music and see what comes out," Andersson says.

"I’d like that, that’d be interesting. Better than recycling again."

If they can recapture some of the magic that made Abba such a huge global success, they could have another hit show on their hands.

It seems the catchy, upbeat songs of Abba which drive Mamma Mia! have earned the group some unlikely fans over the years.

Joe Strummer, of punk band The Clash, was apparently an admirer, while The Sex Pistols’ Sid Vicious once asked Faltskog and Lyngstad for their autographs.

But surely most music fans see The Clash and Abba as polar opposites?

"Yeah, us too," says Bjorn. "But I don’t think styles matter that much – they can recognise if something’s good even if your style was far away from theirs."

So Abba and The Clash had some things in common?

"Yes," says Andersson. "But they didn’t have as nice costumes as we had."

ABBA on 35 years as legends – BBC News
Thank you for the fashions