Off and on four about three years, with and without official backing, small cadre of maroon beret-wearing men has been training to become the Prince George's sheriff's departmental SWAT team.

In its various incarnations, the SWAT team has been described by departmental sources as "a big joke," "an ego trip" and "a county service." To the participants, it's a very serious business.

They meet Saturdays on their own time at the courthouse in Upper Marlboro. At their own expense, they have gone to scuba-diving school.

Recently, Sheriff Don Ansell has sent the group on county time and expense to Fort Meade to learn about bombs. He is sending them in May to a weeklong session sponsored by the FBI on how to deal with hostage situations.

Is it really a SWAT team? "They call themselves that," said a seemingly bemused Ansell last week. "They're very unofficial."

Ansell said the group of about a half dozen deputies first came to him with the idea three years ago. "I said I don't care, you want to get special training, go ahead and get it," Ansell said. So, for a couple of months, the group got together after work and on weekends for running and calisthenics and on at least one occasion, target practice at a National Rifle Association range.

"And then they came back to me," Ansell recalled, "and said, 'Well, we need robes and we need shotguns and we need rifles and we want a whole bunch of crap,' and I said, 'Get outa here. I ain't ordering that stuff through the department. There's no way in God's green earth I could justify it.' They got disgruntled about it and said the shierff's not backing us, and they disbanded."

About a year later, the SWAT team was revived, this time with maroon berets and scuba diving. "There was a fad going around," Ansell said. "They wanted us to form a diving squad. I said if they wanted to do it off duty, I don't care, because about 8 foot of water is about the deepest water we got around here."

The current SWAT team, made up of mostly the same people, formed within the last few months, with more encouragement this time from Ansell.

"They said they wanted to specially train themselves for hostage situations, like at the jail and courthouse," he said. "I told them to put it together, train on your own time, and if you show me you can put something together halfway decent, I'll send you to some schools, and they have.

"I'm afraid that sooner or later, something is going to go down in the courthouse," said Ansell. "When it does, I want a team that's specially trained for that purpose . . . I think it's an absolute necessity."