MY quest this week has been to explain Tony Blair's collars. To some, it is his policies that are a mystery; but to me, you see, it is his neckwear.

In the past week, Mr Blair has changed dramatically. He has taken to wearing distinctive, wide, sprawling collars that show off a huge amount of his tie knot. Most people wear tight collars that show off just a decent amount of tie knot. Indeed, until this week I believed that people who wore the "Oxford collar" were those who shopped in the sales and would wear anything if it had a fiver off.

Mr Blair would appear to have purchased a job-lot of these shirts last weekend, because he wore a blue one in Cardiff on Sunday; he wore a purple one in Leeds on Tuesday, and he wore a pink one in London on Thursday.

This type of collar was apparently popularised by Humphrey Bogart in the 1940s, but until this week, the only Cabinet member who favoured them was Jack Straw.

But there is more to the collar and tie than meets the eye, as Mr Blair may one day come to know to his cost:

* Although the ancient Egyptians and the Romans dallied with neckerchiefs, the inventors of the modern tie were Croatian mercenaries in 1660. King Louis XIV invited them to France to celebrate their victory over the Turks, and they rode into Paris with gaily coloured pieces of cloth tied around their necks. The French were mightily impressed, and called these things "cravats" - apparently a corruption of "Croat".

* The cravat reached England in 1660 when Charles II reclaimed the throne. After the Puritan rule when gambling, drinking, music, dancing and fun were all abandoned, England was in a party mood - and how better to celebrate than by tying strange things to your neck?

* There have been some extremely silly collar fashions. In the 18th Century, French and Prussian soldiers had to wear "the stock" which was a fierce piece of starched material that thrust their necks forward and pushed blood into their faces which the generals thought made them look very warlike. However, the soldiers were ordered to tie the collars so tight that their eyes bulged and they fainted, or they suffered from nosebleeds or vertigo.

* Just as silly was the French "incroyable" collar which covered the ears and held the cravat over the nose and mouth. It was also fashionable to sprout whiskers from your cheeks, so the wearer was almost entirely hidden.

* "A well-tied tie is the first serious step in life." - Oscar Wilde (Importance of Being Earnest).

* In the US, 80 per cent of ties are bought by women.

* The "Windsor knot" - large and bulky and designed to be worn in a wide, Blair-style collar - was popularised by Edward VIII shortly before his abdication in 1936. Ronald Reagan wore a Windsor throughout his presidency.

* Fashion experts believe Napoleon lost at Waterloo because of his cravat. Normally he wore a black silk one, but on the day of the battle he foolishly changed and wore a white one with a flowing bow.

With this shocking revelation, my quest to explain Mr Blair's collar conversion comes to an end. Mr Blair clearly expects to lose his Waterloo, his great European battle over the EU constitution, and when the referendum result comes in he will be able to blame, with historical accuracy, his choice of neckwear.