There is some disagreement among pundits here on the question of where Michael Heseltine got the nickname "Tarzan."

Some say it stems from his mane of blond hair, which, although usually swept back with care from his broad forehead, tends to fly out in dips and wings, Johnny Weissmuller-style, in a brisk wind or moments of extreme political excitement.

Others, however, say it comes from an incident in May 1976. Heseltine, then in the Tory opposition under a Labor Party government, became incensed when Labor backbenchers in the House of Commons broke into song, with a rendition of "The Red Flag." Heseltine jumped from his own bench, seized the ceremonial mace from the table before the speaker of the house, and began swinging it over his head.

What has not been in doubt is Heseltine's image as a spark of color in the generally colorless Thatcher Cabinet, a group of somber men who, despite their political and executive abilities, tend to put the public to sleep.

Heseltine's dramatic resignation from the Cabinet today, after a public dispute with the prime minister, will do nothing to diminish that reputation. What is not known, however, is whether it will be a plus or minus in ambitions he may have to take the prime minister's place.

To talk about his potential for Conservative Party leadership at this point, Heseltine said in a news conference, is "to trivialize" the whole point of principle, and the issue of European defense cooperation, over which he resigned.

"I am not interested in discussing my future within the Conservative Party," he said. "I am a member of Parliament, and if the electors of my constituency continue to return me, I will stand at the next election. I would never dream of standing except as a Conservative candidate."

But there was widespread speculation in political circles today that, having taken such a public stand against Thatcher, he could serve as a lightning rod for increasingly loud rumbles of public and political concern over her somewhat abrupt style of leadership. Although there is virtually no doubt that Thatcher will lead the party into the next election two or three years from now, it also is assumed that that will be her last electoral race.

Despite Heseltine's consistent prominence in the press and rise in government, his reputation within party parliamentary ranks is that of a loner, uninterested in the backslapping and back-room negotiations that are vital components of a leadership bid.

An admirer of Winston Churchill, Heseltine, 52, has a long string of successes behind him. Believed to be the wealthiest man in Thatcher's Cabinet, he came into government as the head of a profitableempire in business publishing.

Elected to Parliament in 1966, within three years he was chosen Conservative opposition spokesman for transport. He was 36. When the Conservatives came to power under Edward Heath in the early 1970s, Heseltine was given a series of junior government posts in transport and environment, eventually becoming minister for aerospace in 1972.

He was a supporter of Heath and an ardent member of the Bow Group, the traditional Conservative parliamentary organization that veered away from the right wing of the party as it emerged under Thatcher. He still is considered a leading party "wet," or liberal.

But Heseltine successfully blended in with the new Tory leadership. When Thatcher won the 1979 election, he was named to the Cabinet as environment secretary.

Given the opportunity to combine his business acumen and activism, Heseltine was in his element. He reorganized the department, slashed the top-heavy bureaucracy to the bone and installed a new management system.

During the 1981 riots in Liverpool and Brixton, Heseltine enhanced his activist, "can-do" reputation as he traveled to strife-torn inner cities and set about trying to organize private business investment in them.

Along the way, Heseltine also became the darling of the often-lackluster yearly Conservative Party conferences. He could always be counted on to give a rousing speech, and the gavel-to-gavel television coverage of the event gave him more nationwide exposure.

Named defense secretary in 1983, he implemented similar reorganizations, and, although defense chiefs were initially fearful of him, they came to respect him. Always active, he frequently was photographed visiting some military base, dressed in combat fatigues, to try out a new weapon or drive a tank.

Describing himself today as "passionately" pro-American, Heseltine was in the forefront of pushing for British deployment of U.S. cruise missiles here, and considers himself personally responsible for breaking the back of pacifist opposition.