Constable Graham Morris, 33, stationed at Marylebone, in central London, said he knew it "would not go unnoticed".
An officer for 15 years, PC Morris claims he is the victim of sex discrimination because his superiors in the Metropolitan Police ordered him to cut off theponytail.
He argues that under Equal Opportunity law he should be allowed to wear his hair long, like his female colleagues.
On the third and final day of the London hearing, he said he decided to keep his hair long when he was returned to uniformed duty in November 1993 after working undercover with a pickpocket squad.
The officer said that although he believed his hair was tidy, he knew the ponytail was in breach of the regulations. "I do not wish to discuss the reasons why I was returned to uniform duty," he said, "but I realised if I turned up at work with my hair in a style such as it was, it would not go unnoticed.
"I had chosen to have my hair in that style as a matter of personal choice. But I received a disciplinary punishment which will stay on my record for four years."
PC Morris, whose hair is now cut in the a classic "short-back-and-sides", says that his actions were spurred by strong beliefs in equality rather than by frustration at being forced back into uniform because of irregularities in the way he filled out his time-sheet.
The hearing closed with the panel deciding to reserve its decision until a later date.
Dinah Rose, a spokeswoman for the Metropolitan Police, said yesterday that PC Morris's ponytail was untidy and unacceptable. "This was not a properly grown ponytail or attractively groomed by any stretch of the imagination," she said. "It was a clump of hair which has been described as looking like a doctored dog's tail and looked extraordinary."
She added that if a female officer sported such a hairstyle, the officer would be told by a sergeant to "tidy it".