WHEN released in 1974, Rick Wakeman’s solo album, Journey to the Centre of the Earth, sold 15 million copies and topped the album charts.

“Actually,” Rick tells me during a break in rehearsals, “It got to Number One on my 25th birthday.”

But that was 40 years ago, and that means . . .

“Yeah, not long after the tour, I’ll be 65.”

The tour in question is a 40th anniversary celebration of the album and it’s to be a full-blown performance of the album as Rick will be joined on stage by The New World Symphony Orchestra, The English Chamber Choir and the English Rock Ensemble.

In fact, it’ll be a double celebration as it’s also the 150th anniversary of the publication of the original book by Jules Verne.

The story behind this musical event is a long one, and Rick tells it with his usual humour.

“After we toured the album in 1974, we lost all the music – it just disappeared and in those days it was all hand-written with no computers, so we have never been able to tour it since then.

“Then, when I moved to my new house, we started gathering all the boxes that I had in storage all over the place and a cardboard carton arrived from Australia and it got put in the garage with about 70 other boxes.”

Luck took a hand next.

“Well, it was a couple of months later and I went through this box and it was full of music, but strangely enough, none of it was mine, until I got to the very bottom and there was the Conductor’s score for Journey.”

But there was a problem.

“It was badly water-damaged – in fact, it was basically a papier mache brick.”

“My wife, Rachel, told me to contact Guy Protheroe, who had worked on the original album.

“It then took Guy six months to sort it out but he got it all on a computer.”

The original work was almost an hour in length, but had to be edited down to about 36 minutes to fit on a vinyl album.

“Guy asked me if we could pull together all the missing bits and wouldn’t it be good to go into the studio and record the complete version and correct all the errors that cropped up in the live album.”

“The resulting album is out in June and we’re thrilled to bits with it.”

Well known for taking risk, Rick then though he should take it on tour.

“I’d done an article about it for a magazine and the website went nuts. Thousands of people asked if we could do it live.

"I spoke to the band and they were up for it, but then we had to speak to Thomas the Bank Engine – as we call him – and my management, who both said it was suicidal.

“Fine, I said, we’ll do it.”

The response was such that the original number of dates was doubled and the tour begins today and runs until May 10.

“The amazing thing is that everyone involved has given more than 100 per cent.”

Rick is also keen to point out that the fans are his main driving force.

“It wouldn’t have happened if it wasn’t for the fans,” he said.

“They loved the version of the album that was released as a fan-pack in 2012, and you learn from what other people say.”

The album will come in a variety of formats, with CD, vinyl, deluxe editions with newly discovered photos and exclusive Roger Dean artwork.

“Roger’s artwork is fantastic,” said Rick about the man whose album designs have become legendary.

But there were some problems in transferring the album to live performance.

“Firstly, every stage is different and we have to plan where everything goes. I don’t know about not being room to swing a cat, there’s not room to even hold a cat!”

Next was the narrator.

“Sadly, David Hemmings, who narrated the original album, is no longer with us, but his widow and daughter will be coming to see the show at the Royal Albert Hall, so that’s nice.

“On the new version of the album, I’ve got my old mate Peter Egan (Ever Decreasing Circles), as yopu really need a storytellers’ voice, and Peter was perfect.

“However, he’s contracted to appear at The Old Vic, so he suggested Phillip Franks (Darling Buds of May, Heartbeat). I didn’t know Philip, but Peter rang him for me and he jumped at it.”

Rehearsals have been hectic.

“I’ve not been getting home till gone midnight and up again at about half past four, so I’m knackered, but I’ll rested over Easter – my wife has put her foot down.”

Rick has had a few health problems over the years, but he feels okay now.

“Health-wise I’m very good – touch wood. I love life – I open my eyes in the morning and think ‘well, that’s another day I’ve got, let’s get on with it’; then I have a quick wander around the garden rain or shine.

“The actual show will be in two halves, the second half is the actual performance of Journey which is about 65 minutes and then an encore – if we get one – of about 15 minutes, which we hope will be something special.”

Rick has also got something special lined up for the first half.

“It’s going to be me and my piano, and I’ll be telling the stories about what happened when we toured Journey originally. There will be stories of flatulent dinosaurs and it’s really silly, plus I’ll be playing some of the music that influenced me when I was making the album.

Rick Wakeman, with The New World Symphony Orchestra, The English Chamber Choir and The English Rock Ensemble will be performing Journey to the Centre of the Earth at the O2 Apollo Theatre, Manchester tomorrow.