Sombre is not a word often associated with Bill Clinton. This is a man with a vivacious personality, who has suddenly discovered the vivacious clothing that goes with it.

Today the former US President emerged from behind the solemn black door of 10 Downing Street wearing a veritable rainbow of colours: a dazzling pistachio shirt, an eye-popping striped tie and a raffish summer jacket in dove grey, the season's most fashionable shade.

The panoply of citrus shades was accessorised with a golden tan and perfectly coiffured wisps of white hair. Life is good in the Clinton camp and Bill is not ashamed to show it, especially to a certain presidential candidate.

This week Donatella Versace dedicated her menswear collection to Barack Obama , “a relaxed man who doesn't need to flex muscle to show he has power”. And neither, it seems, does Bill.

Not prepared to take a back seat in the race for most modish Democrat, Bill Clinton's message to his sartorial adversary was clear: I can wear trendy ice-cream shades just as well as any Versace muse.

The relatively sudden onset of vibrant attire stands in stark contrast to the navy suit, white shirt, plain tie triumvirate that characterised Mr Clinton's uniform during his presidential term.

Now that his wife's fierce political battle has drawn to a close, he has more time on his hands for the finer things in life, such as clothes and parties. And where better to reveal your more flamboyant side than at the star-studded 90th birthday of Nelson Mandela? He had obviously been watching with a keen eye the catwalks of Milan this past week and absorbing every trend and applying every rule: lightweight tailoring, ice-cream colours and lots of vivid stripes.

Anything to usurp Obama in the fashion stakes.