He's seen the highs and lows before. Don't write him off yet

We all know the answer to that. And its not "up".

When he signed an astonishing 80 million contract with EMI in 2002, Williams was the most successful solo artist in UK pop history. In 2003, he performed to more than half a million people at three consecutive sold-out nights at Knebworth. But by the time of his 30th birthday in 2004, he had fallen out with his co-songwriter and producer, Guy Chambers, publicly declared his disinterest in cracking the US market and embarked on a series of increasingly personal yet commercially dubious albums culminating in last year's erratic and poorly received Rudebox.

A bizarre hodge-podge of rap and dance, it has been the lowest-selling album of his career. Out of contract with EMI, Williams ended the year watching his former band Take That ascend to the number one slot, while openly hinting that his own recording career was over.
That he has wound up back in rehab is the least surprising aspect of his decline.

A compulsive character prone to depression, he has declared his addiction to so many things (from Class A drugs to shopping, sex and computer games), it is a wonder there are any left. Yet on Good Doctor, an apparently jokey rap track from Rudebox, he makes explicit his new found fondness for prescription drugs. The song contains references to Xanax, Vicodin, codeine, morphine, opium, methadone, Menocrabedene, and a variety of others.

Yet it is Williams's open display of his neuroses that have made him such a compelling pop star. Despite his cheeky chappy persona, he exhibits a contradictory combination of ego and insecurity, arrogance and vulnerability, more usually associated with credible rock icons such as John Lennon and Kurt Cobain.
The dissolution of his hugely successful song-writing partnership with Guy Chambers is probably the root of Williams's decline.

Without the sure pop instincts and restraining influence of Chambers, his music has become more neurotic and less commercial.
Yet it would be a mistake to write Williams off. He has been down before.

When he left Take That in 1995 and embarked on a mammoth drug and drink fuelled binge, he was widely dismissed as one of pop's losers. In the soap opera of rock and roll, sometimes you've got to go down to get back up again.