THE first thing that strikes you about Elaine Paige is that she really is a tiny lady to produce one of the biggest, most iconic voices in musical theatre; the second is that she looks a good decade or more younger than her 66 years.

In an era in which a win on the X Factor can see you labelled a “superstar” – or even more ridiculously “a legend” – Paige is the real deal. This year she marks both her 50th anniversary in entertainment and a decade behind the microphone presenting her weekly BBC Radio 2 show.

To commemorate these landmarks she’s off on a world tour that brings her back to Sage Gateshead in October. She’s also decided to prefix it with the word “farewell”.

But why is she calling it a day now? And will she be just another of those acts who bows out one year and is planning their comeback the next?

“Why does no one believe me?,” she says with a trace of the trademark giggle that will be familiar to her two million radio listeners. “I’ve never said I’m retiring and I’ll do occasional concerts, but what I am saying farewell to are the lengthy tours, the travelling and sleeping in a different bed every night for weeks. In the past few years I’ve toured the US, Australia, New Zealand, China, the Far East and Scandinavia and I’ve also toured the UK every few years for almost three decades. I’ve thought long and hard about this decision, but feel this landmark event, my 50th anniversary, is a good time to bid adieu.”

What her loyal audiences come to hear are selections from a career that reads like a history of the modern musical and an artist who delivers each song charged with emotion and as if it were a three-act play.

“I tend to think of myself as an actress who sings rather than a singer who acts so I approach everything as a storyteller. The beauty of musical theatre songs is that they come from characters so they really give you something to work with in the way a pop song wouldn’t.”

From early roles in Hair, Jesus Christ Superstar, Grease and Billy (in which she managed to steal some glory from Michael Crawford) to Cats, Chess, The King & I, Anything Goes, Piaf, Sweeney Todd and Follies, it’s hard to think of another performer this side of the Atlantic who comes close.

In among those successes however was the perhaps the biggest of them all and one which, as she says, “gave me a career”.

In 1978 she secured the role of a former Argentine first lady, seeing off competition from 400 actresses and, as Eva Peron in Rice and Lloyd Webber’s Evita, delivered a career-defining performance those who saw it rave about almost four decades later.

It hasn’t all been plain sailing. She’s enjoyed enduring success in a notoriously fickle business; she’s suffered media intrusion; she’s had breast cancer, and she’s had to deal with what some see as the creative stigma of having been so closely associated with the work of Andrew Lloyd Webber.

He, though, is full of praise. Speaking of her performance as the deranged silent movie star Norma Desmond in Sunset Boulevard, Lloyd Webber says: “It’s rare for me to stand and applaud one of my own songs… but I couldn’t help but respond in exactly the same way as the rest of the audience. She caught quite magnificently the essence of the moment and what that song was all about.” And during a South Bank Show on her career, he added: “She dares and because she dares she thrills.”

Norma Desmond was the role that eventually took her to Broadway after union wrangles prevented her recreating her successes Stateside in Evita, Cats and Chess.

The notoriously Rottweiler-like New York critics, however, made the 15-year wait worthwhile. One described her as “probably the most remarkable voice of the popular musical theatre today”, while another implored “one can only hope she’ll immigrate here permanently”.

We think of her as a very British star but her career is international. She was the first Western musical theatre artiste to perform in China and has been invited back several times (“It’s one of the few places I can get shoes that fit!”) she’s headlined at the Sydney Opera House, Bolshoi Theatre in Moscow, Lincoln Center in New York, and she sang at the White House for President and Mrs Ronald Reagan.

You get the sense Paige is now at her most relaxed and content. She’s a keen and, by all accounts, accomplished tennis player and she’s enjoying the “normal” things such as dinner with friends and going to the theatre (interestingly she’d always opt for a play over a musical) that the rigours of performing an eight-show week make almost impossible.

She’s also passionate about helping the next generation of performers and gives generously of her time to support students at a number of drama schools and through various education programmes.

“I’m blessed in the career I’ve had and have spent much of my life going from one show to another, thankfully for the most part, in long runs. But theatre, and musical theatre in particular, is demanding. It’s a young person’s game. For me, it had to be about leading the life of a nun – eating well, sleeping well and conserving every ounce of energy.”

So what can audiences expect from this tour? “I’ll sing the hits, of course, but I spent a lot of time this year looking back at my recordings of the past 30 years for a new compilation album so I’m hoping to include some things I’ve never, or rarely, sung in concert.”

And after she hangs up her touring shoes?

“Oh, I think I’ll just grow old disgracefully!”

And you’re left in little doubt that should she choose to she’ll do so with all the qualities that have given her a career unequalled by few. In the meantime, she strikes you as someone who would never shy away from a new challenge.

  • The UK leg of Elaine Paige’s farewell tour reaches Sage Gateshead on October 14 (sagegateshead.com). Elaine Paige – The Ultimate Collection is out now