Prince Charles, in an interview broadcast Saturday night on CBS-TV, said he has a "well-developed conscience" and believes it is proper for him to champion environmental and other causes.

"My trouble is that I said I feel very strongly about things. I can't help it," Prince Charles said on CBS's "West 57th" in his first U.S. interview in five years. "I must express it. I wouldn't be true to myself if I didn't."The prince of Wales said he has taken to speaking out on a variety of subjects - including urban planning, architecture and the environment - and feels he should continue to do so.

"I've always felt, anyway, that the important thing is to be relevant to people's needs and aspirations, as far as somebody who is in my position is concerned," he said. "And nobody else is in the position that I'm in, so nobody else actually knows what is involved or what it's like."

Prince Charles expressed satisfaction that many of his views, particulary those on the environment, are now taken seriously by politicians. He called the environment "the biggest political issue of our day.

"But I've been talking about the environment for quite a long time when I was just dismissed as a crank," he said. "Now, I'm going to go on talking about it."