John Lennon would have been 70 this month. What would the mercurial, tempestuous ex-Beatle have been doing in 2010? Touring the world with a reformed Beatles? Running a chip shop in Liverpool with Yoko Ono? Judging The X Factor? There's just no knowing.
But to commemorate his 70th birthday, a comprehensive set of reissues has been released, flooding the market anew with Lennon material. This campaign sees a titanic box-set anthology (the third Lennon box in the past decade), two new sets of hits compilations, and each studio album from 1970's post-Beatles Plastic Ono Band through to the 1980 "comeback", Double Fantasy. There's a new, remixed edition of the latter too, stripped of its rather gaudy 1980s production. And only purists and masochists will lament the absence of the three nearly unlistenable albums of "experimental" electronic scrabble and screech recorded with Ono in the late 1960s.
But the most remarkable aspect of Lennon's solo career is not the gradual decline in the quality of his music throughout the 1970s, but rather, the perpetually fascinating way in which he managed consistently to capture and distil his environment and preoccupations so vividly. The legacy is a stark reminder that Lennon was the first British pop musician to explore identity, insecurity and emotional anguish to any serious degree, through these fascinating snapshots into a life lived to the full, right up to the moment of his murder in December 1980.
At the start of the decade, reeling from the traumatic split of the Beatles, in therapy and trying to deal with decades of assorted traumas and psychological issues dating back to childhood, Lennon was in bad shape. The spare, cathartic Plastic Ono Band album issued in late 1970, recorded after months of controversial "primal scream" therapy, is still astonishing in its visceral impact. It sounds as if it was sent up from a padded cell. Nowhere in the history of pop music has there been such a devastating disavowal of fallen idols as in the climactic verses of God, in which Lennon angrily denounces former touchstones including Elvis Presley, John Kennedy, Bob Dylan and - in a final anguished yelp - "Beatles!" before asserting his belief only in himself and Ono - "and that's reality".
From this, 1971's Imagine softens and seduces with the most Beatle-like suite of songs of his canon. Much more than the ubiquitous title track, Imagine is a complete tour through the world of John Lennon. From his residual bitterness at Paul McCartney in How Do You Sleep to the gorgeous confessional of Jealous Guy, obsessive love in Oh Yoko and aching insecurity in How?, it remains his most fully rounded, substantial album, and signalled his farewell to Britain and, to a fair extent, his troubled past.
As chronicled in Michael Epstein's new documentary, LennnonNYC, fresh adventures awaited in New York. There he fell in with a group of radical activists and revitalised leftovers from the 1960s protest movements. His next release, the one-size-fits-all protest of 1972's Some Time in New York City flopped abysmally. Real life was intruding, his marriage to Ono was in danger of collapsing and for a man so steeped in the entertainment business, he realised there was a very real danger that the hits were drying up. The lacklustre 1973 set Mind Games serves as ample proof that, despite a rather painful attempt at Beatlish whimsy in the title track, Lennon was struggling personally, professionally and emotionally.
Separating from Ono and moving to Los Angeles heralded the start of a 15-month debauch. Again, the diary-like aspect of his music at the time, in 1974's Walls and Bridges and 1975's ghastly Rock'n'Roll suggests that the bottom had been reached, with dissipation in various forms, guns in the studio and sloppy, maudlin covers of old rock classics. It was time for Lennon to reassess his life, and after his reconciliation with Ono the following year, and the birth of their son Sean, he took probably the most radical career choice available: to withdraw entirely from the pop scene. Which is why the release in 1980 of Double Fantasy, a pleasant collection of gentle rock numbers, is all the more tragic in hindsight. Having finally achieved the peace and inner contentment that had eluded him throughout his adult life, he was assassinated mere weeks after this latest diary instalment was issued.
The loss felt by the world remains clear, as shown by the massive success of reissues and promotions such as this campaign, 30 years on. But the genuine artistry that underpins this erratic, occasionally brilliant, sometimes awful body of work is assurance that his work is as universal and relevant to listeners now as it ever was.