AS of yesterday, I am no longer six feet tall. I am 1.83 meters - and that's official.
As a law-abiding citizen of the European Union, suddenly, if I try to sell anyone a gallon of petrol, I could wind up paying a fine of $8,000 or even going to jail. Sales in gallons are now unlawful. It has to be liters.
Like all other British citizens, and by order of the government, I have been metricated.
The experience has not made me feel much different, and I am not irate. That cannot be said of thousands of traders, and millions of their customers, who are up in arms at having to give up the old Imperial system of weights and measures and embrace a European standard.
As with many things in Britain these days, Brussels, headquarters of the European Union, is setting the pace. Under EU rules, all member states are supposed to use the metric system. Until yesterday all did - except Britain.
In 1972, Britain began a slow adjustment. Pounds of butter appeared on supermarket shelves with a metric equivalent stamped on the price tag. Scales, hitherto graduated only in ''stones'' (14 pounds), showed kilograms as well.
But now Imperial measures are out, metric measures are in, and a mighty row is ensuing.
Opponents of the change have formed the Imperial Measures Preservation Society and plan to go to the European Court of Justice in Luxembourg to challenge enforced metrication.
Vivian Linacre, the founder of the group, says: ''We will use the European Union's own antidiscrimination rules, enshrined in the Treaty of Rome, to resist this process. It will be an open-and-shut case.''
Mr. Linacre, a surveyor, says the changes ''strike at the very heart of a national institution.'' He is not alone in his fury.
The Federation of Small Businesses, which represents most of Britain's small traders, has issued thousands of ''Metric Madness'' posters urging people to fight the change. Nicholas Goulding, speaking for the Forum of Private Business, calls the switch ''ridiculous kowtowing to the EU.''
Apart from ordinary British stubbornness, two main factors lie behind the buildup of resistance.
Although British schools have taught the metric system since 1974, many older people do not understand it, and store owners say their customers will be greatly confused.
A worse problem is that, in a typically British way, the government has fuzzed the issue by creating a string of exceptions.
At the butcher's shop, pre-packed mincemeat [ground beef] now has to be labeled metrically. But loose mincemeat can be sold in pounds and ounces for another five years.
Measures classified by the Department of Trade and Industry as ''descriptive'' can remain Imperial. Thus a 12-inch pizza or a quarter-pounder hamburger will remain legal. But cloth must be sold in meters and centimeters.
Such anomalies have given so-called Eurosceptics - people who don't like the EU anyway - a chance to vent their wrath at Brussels.
The right-wing European Foundation, the Campaign for an Independent Britain, and the UK Independence Party all have climbed on the antimetrication bandwagon.
Bill Cash, chairman of the European Foundation, says: ''I am not into gesture politics, but I resent the way this matter has been handled.''
Last Friday, Linacre called for a national campaign of civil disobedience. Some storekeepers got in ahead of him.
In Cornwall, in southwestern England, a chain of superstores declared itself against the ''Brussels edict'' and erected road signs saying ''Rule Britannia in inches, not meters,'' and ''Common sense is now a criminal offense.''
Bruce Robertson, the chain's chairman, says: ''Most of my customers would no more be able to tell me how many feet and inches there are in a meter than who was the last president of France.''
Another citadel of resistance is in the heart of London. Savile Row is where the best English hand-tailoring is done. John Davis of Tobias Tailors, which clothes British government ministers, decided to ignore yesterday's Metrication Day.
''I foresee rebellion,'' he says. ''I am aghast at the thought that by providing my customers with my time-honored service I will be in breach of the law.''
Whether metric-proof barriers can be erected around the British Isles, however, remains in doubt.
Antimetric activist Linacre notes that ''as a magnanimous concession to British sensibilities, Brussels is allowing us to keep the mile.'' But he doubts whether kilometers can be held at bay for long.
If he is right, opponents of the European standard soon may have only one option left: Head for North America where the long arm (metrically measured, of course) of Brussels has yet to reach.