Amy Jenkins: Whether back for good or not, Robbie's return could be magic

Are you Robbie Williams or are you Gary Barlow?

Are you wayward and unpredictable with a tendency to depression and the odd flash of genius? Or are you a solid and dependable hard worker, the decent one who eventually wins through? I put myself more on the Robbie side of the equation – although I'm always trying to call forth my inner Gary Barlow to balance things. So there's something for everyone in the Take That story – and now there's redemption too. The errant Williams has been welcomed back into the Take That fold and an archetypal drama has come full circle.

Williams left the band 15 years ago due to a clash of egos with Gary Barlow. Barlow was the songwriting talent but Williams was the one that the term "X-factor" might have been coined for. Leaving Take That turned out to be a good move and it became clear he was a proper pop star – in some ways an old fashioned entertainer, the kind who has show business running through his veins. He bowled us over with "Angels", a song that became a kind of national anthem. After that we just called him "Robbie".

As his star went up, Barlow's went down. Take That disbanded and Barlow's nadir came when ITV made a "where are they now" documentary centred around the band's first reunion in 2005, nearly 10 years after their split – a reunion that Williams didn't even attend. In a moment of excruciating awfulness, the former band members sat in a hotel room waiting to watch a video message from the busy Robbie in Los Angeles. As they were struggling with the disappointment of their post-Take That lives, the expressions on their faces had to be seen to be believed. Barlow's humiliation was complete.

All seemed lost, but it turned out this was only the end of the second act. Barlow picked himself up, dusted himself down, got his light out from under the bushel and wrote a monster hit called "Shine". The Take That comeback was a runaway success and now it was Barlow who was unstoppable. When he welcomed Paul McCartney on to the stage at the end of his triumphant Children in Need concert last November, we saw in Barlow a man who had earned the respect of his peers and refound his dignity.

But what of Act Four? As with politics, all pop careers end in failure, I suppose – or at least a well-cushioned retirement. This latest twist makes overwhelming financial sense for all concerned. Williams is currently in want of rehabilitation, although not – for once – the drying-out kind. He needs to refocus his talent and halt his Howard Hughes tendencies of late. (He has a UFO obsession.) Meanwhile, the four-man Take That have broken all records with the success of their Circus tour, but are in danger of hitting the inevitable "the only way is down" syndrome. What better way to refresh the brand, as they say, than bringing Williams back on board?

So they're in it for the money, but it doesn't matter. It's still a great story. Barlow and Williams have written a duet called "Shame". Quite apart from the merits of the actual music, whatever they may be, who can fail to be a little bit interested in how events turn out?

Since the days of the prodigal son, we've been gripped by stories of families becoming whole again – and there's something undeniably compelling about this week's photographs of Williams with Barlow and his former bandmates. "It feels like coming home," Williams said – and the part of us that wants to mend our own broken families (whether they are actually broken or not, to the Oedipal child they always seem so) can hardly help breathing a sigh of relief.

Such is the power of the archetypal myth. "Life is beautifully strange sometimes," said band member Jason Orange. "I'm over the moon that Robbie's back with us, however long it lasts."