For the first time in 20 years, Mamma Mia! is being performed outside – at Harewood House

Likewise, The Rocky Horror Show, which opened upstairs at the Royal Court in 1973 before it had the whole world doing the time warp.

The fact that they are both stories of the underdog idea – a rap-musical about the Founding Fathers, a musical tribute to B movies featuring as its hero a ‘sweet transvestite from Transsexual, Transylvania’ – that captures the imagination. The notion that it really shouldn’t work, but it does, is what captivates me.

At the other end of the spectrum is Mamma Mia!

Judy Craymer, the show’s producer has said in the past that it was an unknown quantity, that ‘we really had no idea how it was going to be received’, to which your response might reasonably be a raised eyebrow and the single word ‘really’?

Cramer had been carrying the idea around in her head for a decade before the opening night of Mamma Mia! (exclamation mark categorically not ours, but there at the insistence of the creators) on March 23, 1999.

When the opening night arrived, the response was immediate, fervent and universal. Craymer has said in the past that ‘the audience went wild, literally out of their seats, singing and dancing in the aisles’. Someone who can attest to the fact that the response remains just as enthusiastic over two decades is Lucy May Barker, who plays the lead role of Sophie in the first outdoor production of the musical in 20 years as it comes to Yorkshire tonight.

“There is a bit at the end of the show, where we sing a megamix and encourage people to get up and sing along and dance and people absolutely get involved in that,” says May Barker has played the role of Sophie for the past six years.

For the uninitiated, Mamma Mia! follows the story of Sophie, a bride-to-be who is preparing to marry on a Greek Island. The one thing missing is a father to walk her down the aisle – because she never knew who her father was. She invites the three potential candidates, former lovers of her mother’s from two decades previously, to the Greek Island for the wedding – hilarity, chaos, heartbreak and resolution ensue.

It is quite remarkable that the songs already written and recorded by Abba were able to fit the narrative, even without the aid of a shoehorn.

Although Craymer claims that she had no idea how the show would be received, it seemed a pretty good bet, given that the music of Abba was recognised for being recognisable the world over. That’s literal, by the way – in 2011 it became the first Western musical ever to be staged in Mandarin in the People’s Republic of China.

May Barker says: “There is something kind of magic about Abba and their music. So many of their songs were such big hits, the lyrics are fantastic and as someone who sings those songs on stage, it feels like they come really naturally.

“The lyrics are often so intimate and specific, in a way that a lot of music these days isn’t specific. The music just has that extra bit of magic that it’s really hard to put your finger on.”

Whatever it was the pop music quartet put their finger on, it worked. Mamma Mia! has given the extraordinary group, who were active in the charts from 1974 to 1983, an unlikely after life.

The musical has been seen by over 65 million people in 50 productions in 16 different languages. It was the eighth longest running show in Broadway history, where it played for a record-breaking 14 years and of course it has spawned not one, but two films starring Meryl Streep.

“The show opened when I was four or five and I still remember the first time I watched it, so when I tried on my costume for the first time six years ago, it was quite a moment,” says May Barker.

“Now we’re bringing the show to a whole new generation and 22 years later we’re bringing it to this amazing venue, it’s an honour to play a part in the story.”

The amazing venue is Harewood House, a place which should be able to stand the vagaries of the pandemic. With audiences able, but still understandably a little nervous about returning to theatres, to have a performance in the open air seems eminently sensible, even in spite of the British ‘summer’.

For audiences craving live entertainment, it will be a welcome sight to see performers on stage again, but it’s also going to be emotional for the performers.

“It’s so exciting to be back. We had our first dress rehearsal last night and it was really special. There are certain songs that were actually really emotional for everyone. I hope it’s emotional for the audiences as well – they’ve been starved of this and it’s something we’ve all missed out on.

“Hopefully we’ll have the sunshine, so we can all imagine it’s like the Greek sunshine of the island.” For May Barker, coming up to Harewood House will be a welcome return to the area.

“We played Leeds on the first UK tour and it was fantastic. Every audience in each city in the UK has its own personality, with some more excitable and some a little more reserved. The Leeds audience were definitely not reserved.”

And after a year away from the stages for performers and audience, it will be a case of mamma mia, here they go again.

Performances will be taking place from August 13 to 30 August, in the grounds of Harewood House. Details: www.mamma-mia.com