Rebel trader Peter Ellis says the war against the metric system is being won following the decision by Tesco to return to pounds and ounces.
Mr Ellis openly flouts the law at his Newhaven business by selling fish in pounds and ounces.
He has still to be prosecuted for his defiance.
East Sussex County Council has said it would not use him as a test case, but will take action once the legislation has proved sound.
He and other rebels who refuse to bow to European stating that prices must be displayed in metric units are delighted at the action by Tesco.
Mr Ellis, 54, director of Network Seafoods at Newhaven, one of the main fish wholesalers in Sussex, has been inundated with letters and messages of support since his fight to keep imperial measures featured in the Argus.
He has challenged trading standards officers at East Sussex County Council to prosecute him.
He openly displays all his prices solely in pounds and ounces, illegally uses pure imperial scales - and his customers love it.
His company does sell in metric when required, but few people demand it.
He said even French visitors on day trips supported him for sticking to pounds and ounces.
Mr Ellis faces a maximum fine of £2,000 and could be jailed for not displaying metric prices.
The law banning the sole use of pounds and ounces for the sale of food was brought in to create uniformity across Europe and to stop British traders gaining an advantage as prices in displayed in pounds and ounces appear cheaper than in kilos and grams.
So far there have been no moves by trading standards officers to prosecute Mr Ellis.
They are awaiting the results of test cases against people elsewhere in the country.
As yet, no one has appeared in court for selling solely in pounds and ounces. The law states that metric measurements must take precedence over imperial and must be in larger type.
Peter Ellis displays everything in pounds and ounces. Metric prices are only available on request.
Mr Ellis, who has become involved with the British Weights and Measures Association, which is campaigning to keep imperial measures, since starting his fight, was delighted with Tesco.
He said: "I am over the moon. This brave move by Tesco is a step in the right direction. I genuinely believe we are winning the war against metric. I am just doing what customers want.
"I can provide metric measures, but nobody asks. I am ready to be prosecuted and we are all waiting for a test case."
East Sussex trading standards officer Roger Wankling said: "We will not be the first authority to force a test case.
"Mr Ellis is breaking the law. As soon as the courts have proved the legislation is sound, we will take positive action."
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