It is tempting to see Kay as a split personality: he was a teenage delinquent who stole and dealt drugs, yet he was such a talented musician that he won a £2 million contract from Sony aged just 19.
He can behave like a thug, and yet he often donates large sums of money to charity.
One of the reasons he split from Van Outen was that he was keener to have children than she was.
We can confirm that two males have each made contradictory allegations of common assault against each other.' It's not the first time that a night out on the town has gone sour for Jay Kay, whose biggest hit, Virtual Insanity, was back in 1997.
Just three months ago, he was at the centre of another spectacular brawl outside another private members' club, Home House in Central London, after the Brit Awards.
According to an onlooker, the trouble began when Samantha climbed into the back of Kay's car and the photographers surged forward to get a better shot of her.
Kay wound down his window and asked them to get out of the way.
He had to be restrained by his own bodyguards, who seem to be wise enough to realise their employer's main danger comes from himself.
On that night, a 'wild-eyed', alcohol-fuelled Kay stumbled on to the street, tried to hurl a glass of vodka at onlookers and shouted: 'I'm going to have you ... I won't have minders with me then.' He was then bundled into his own car.
He'd been a cocaine user for six years, and though he claimed to be clean last year, six weeks ago a topless dancer boasted in a newspaper of her 'coke frenzy' with him in Paris.
Add to this three speeding bans (he's often bragged of driving at 175mph and getting away with it); accusations of threatening phone calls to a former employee which are being investigated by police; becoming the first man to pole-dance at Stringfellow's lap-dancing club last month; and an appearance on live Australian TV in which he kept shouting 'Let my trouser snake out! And yet the drugs, drink and naked aggression don't seem to square with the other side of Jay Kay.
He rolled a joint on stage in Glasgow and only last month announced that he wanted to open his own cannabis cafe.
He's such a heavy smoker that at 30 he was diagnosed with Reinke's edema, a smoking condition.
The key to the Jay Kay conundrum lies in his background.