Terence Blacker: The untold story of an enduring icon of rock

What a fascinating and enigmatic character Sir Cliff Richard is. One moment he is dullness personified, as reassuringly bland as an early-evening newsreader, the next he becomes almost interesting. There was the moment he held hands with Sue Barker, and there was his appearance on a London stage as, of all characters, Heathcliff, and then – oh, there must be loads of interesting moments.

To judge by an interview in the latest edition of Q magazine, one of these occasional spasms of originality has just occurred. The Beatles, says Sir Cliff, were all right in their way but quite often on their records, the guitars were out of tune. George Harrison's solos were particularly horrific. "I couldn't believe that they were in this hi-tech age, and they couldn't go back and do it with a tuned guitar. Being out of tune – I find it unforgivable."

There are two responses to this analysis. The first is that it is complete twaddle; the second that even if George's guitar was out of tune, which it wasn't, that was part of the musical intention. If Sir Cliff listens to Bob Dylan's Blonde on Blonde album from the same period, he might begin to understand that, in the right setting, an out-of-tune guitar or even a badly-tuned piano can be more effective than the most flawless digital recording of, for example, his own "Devil Woman".

Sir Cliff and Bob have more in common than might at first appear to be the case. They are both survivors, but whereas Bob has added surprise, colour and development to music over the past half century, the Peter Pan of Pop has leeched them away.

All the same, Sir Cliff's career should surely now be marked by an official biopic. Todd Haynes's masterly I'm Not There, which portrayed Dylan's life through stories involving six different characters, played by, among others, Cate Blanchett, Richard Gere and Heath Ledger, could act as a template for a film based on Sir Cliff's life. Living Doll would be a perfect title.

Just as the Dylan film captures his early life through a young black actor Marcus Carl Franklin, so Living Doll could have former children's TV presenter Andi Peters taking the role of the young Harry Webb, a suburban lad dreaming of stardom. There will be a telling moment when the young Harry is given a present that will change his life for ever – a comb.

Perfecting his quiff in front of a mirror throughout his early teenage years, Harry decides he needs a stage name. The Christian name would be provided by his new hairstyle, while his parents' enthusiasm for the legendary broadcaster Richard Dimbleby would provide the second. Aged 17, Quiff Dimbleby was ready to launch his pop career.

Persuaded to change his name to Cliff Richard, the singer becomes a British version of Elvis Presley, only without the looks, voice, style, or talent. The perfect actor for this section of the film, when Cliff is successfully pretending to be sexy, rebellious and American would be Leonardo di Caprio. There follows an uneasy morphing from teen dream into housewife's choice, a development which involves a careful, sanitised imitation of sex-appeal, some very unfortunate haircuts and various disastrously candy-floss singles. I see Michael Sheen as perfect for this critical part of Sir Cliff's story.

Would it be too adventurous to cast Paul O'Grady for the non-affair with Sue Barker (played by Sally Phillips)? As a performer, he has that anguished, buttoned-up look down to perfection. After that, the maturing star, who markets on behalf of God while wrestling with the demons of fame, ego, and the need to be get a No 1 hit for five successive decades, could be played to perfection by Charles Dance.

So we reach the golden, autumnal years. The Ultimate Pop Star, now a knight of the realm, spends most of his time listening to Beatles' guitar solos and wondering why they are loved and respected around the world while he is a local joke. Here, surely, in the final scenes of Living Doll is the opportunity for a heart-wrenching, Oscar-winning performance from that other beloved British institution, Dame Judi Dench.