Campaign aides to Sen. Joseph R. Biden Jr. (D-Del.) reacted angrily yesterday to a report that a fellow Democratic contender for the presidential nomination had given at least one journalist a videotape suggesting that Biden plagiarized a campaign speech of British Labor Party leader Neil Kinnock.

Biden himself said he wasn't angry, adding that his rivals may be "a little worried there's some movement" toward him in the race for the Democratic nomination.

The tape, which yesterday's Des Moines Register described as the first example of an "attack video" launched by a political rival, showed an excerpt of a widely discussed Kinnock commercial from last summer's British general election and then an excerpt from an Aug. 23 debate in Iowa in which Biden borrowed the British leader's words.

Biden did appear to drop his own family something of a notch downward on the economic and social scale to appear more like Kinnock. But Biden and reporters covering his campaign said that in speeches before and after that debate the senator has given Kinnock credit for the same passionate rhetoric, which he has used repeatedly in recent weeks -- and in a speech Friday night in Philadelphia.

"I've been using it all over," Biden said in a telephone interview. He acknowledged failing to credit Kinnock Aug. 23 but said many members of that Iowa audience had heard the same words, fully credited to the Briton, in other campaign appearances.

Biden's campaign spokesman, Larry Rasky, was angry.

"What really steams me is that here we are on the eve of the Bork hearings and another Democratic candidate is deliberately trying to undermine Biden who is going to battle on this thing," Rasky said, referring to Senate confirmation hearings on Robert H. Bork's nomination to the Supreme Court, over which Biden will preside next week. "Somebody has committed an outrageous act here."

Spokesmen for several key Democratic campaigns denied that they had any hand in giving out the videotape. A story in The New York Times yesterday also laid out the similarities between Kinnock's campaign and Biden's, but The Times did not say whether it had received the information from a Biden rival.

Times Washington bureau chief Craig Whitney said the paper did not get a videotape but was tipped off about the similarities between the Biden and Kinnock rhetoric. "We got a tip that it would be worth looking into," he said.

The Kinnock commercial, which was part of a Labor Party broadcast that many British viewers saw as an American-style advertisement, showed the Welshman saying at one point: "Why am I the first Kinnock in a thousand generations to be able to get to university? . . . Was it because our predecessors were thick? . . . Was it because they were weak, those people who could work eight hours underground {as coal miners} and come up and play football, weak? . . . It was because there was no platform upon which they could stand."

Biden, in the Aug. 23 debate said: "Why is it that Joe Biden is the first in his family ever to go to a university? . . . Is it because our fathers and mothers were not bright? Is it because I'm the first Biden in . . . generations to get a college and a graduate degree that I was smarter than the rest? . . . Was it that they didn't work hard, my ancestors who worked in the coal mines of Northeast Pennsylvania and would come up after 12 hours and play football for four hours? . . . It's because they didn't have a platform upon which to stand."

Biden aides said yesterday that Biden began using the Kinnock rhetoric in August and had credited Kinnock on virtually every other occasion when he used it. John Quinlan, a reporter for the Sioux City Journal, said his notes showed Biden said he was quoting Kinnock when he used the same passage in a speech Aug. 14.

Stories in The Times, The Boston Globe and other newspapers also said Biden had used the rhetoric and credited Kinnock for it.

Biden's father, a former auto salesman now in real estate, confirmed that his son is the first Biden to go to college -- although not the first in the whole family. Joe Biden Sr. also said some relatives worked in the Pennsylvania coal fields.

"But they were not miners, they were mine engineers," he said. Biden said last night his great grandfather was a mining engineer.

Several political operators said they found news of Biden's British connection more amusing than a sign of any campaign problem. "You don't copyright these things," said an official from another Democratic campaign. "Everybody borrows from everybody else's successful campaign speeches."

Kinnock may have done a little borrowing of his own for the famous commercial, according to Michael White, Washington correspondent for The Manchester Guardian.

Part of the Labor leader's advertisement showed Kinnock and his wife walking along the top of a cliff along a rugged shoreline. Said White: "There were debts here to {John F.} Kennedy."