LONDON, AUG. 27 -- A jury today convicted four prominent businessmen, including the former head of Guinness PLC, for misconduct involving the brewing giant's multibillion-dollar takeover of a Scottish distiller four years ago.

The convictions closed a chapter in what became known as the biggest white-collar fraud case in British history, and revealed the seamy side of the country's explosive financial-market growth last decade.

The scandal tainted some of the most respected names in British business and uncovered what investigators called a web of greed and deceit that in many respects mirrored Wall Street's insider trading scandal of the late 1980s.

After nearly a week of deliberations, the jury returned guilty verdicts on 19 of 20 counts against former Guinness chairman and chief executive officer Ernest Saunders; Gerald Ronson, chairman of Heron International PLC; former stockbroker Anthony Parnes; and millionaire financier Sir Jack Lyons.

Four other men still face trial for their alleged involvement in the scheme to illegally arrange for the purchase of Guinness stock during the takeover fight for Distillers Co., a maker of Scotch whisky and gin, in 1986.

Saunders, 54, was convicted of two charges of conspiracy to contravene the Prevention of Fraud (Investments) Act, eight charges of false accounting and two charges of theft. He was acquitted of illegally destroying documents.

Ronson, 50, was found guilty of conspiracy to contravene the same law, two charges of false accounting and one of theft.

Parnes, 44, was found guilty of four charges of false accounting and two of theft.

The jury convicted Lyons, 74, on two charges of conspiracy, three charges of false accounting and one of theft.

The four were accused of orchestrating an illegal operation to support Guinness's stock price through undisclosed purchases of Guinness shares, and thus make the brewer's $5.18 billion offer of cash and stock more attractive than a rival bid from supermarket operator Argyll Group PLC.

Guinness succeeded in April 1986 in what was then Britain's largest takeover. In December of that year, the Department of Trade and Industry announced it was investigating, and Saunders was arrested in May 1987. Other arrests followed.

The judge ruled that because of the complexity of the case it should be split into two trials.

In the second trial, expected to start in October, Saunders will again be a defendant, along with Roger Seelig, 44, former corporate finance director for Morgan Grenfell and Co.; Lord Patrick Spens, 47, former director of corporate finance at the merchant bank Henry Ansbacher and corporate finance partner of the investment firm Cazenove and Co.; and David Mayhew, 48, senior corporate finance partner at Cazenove.

They have pleaded innocent to all the charges.

The eighth man is U.S. lawyer Thomas Ward, whom British police are seeking to have extradited from the United States. Ward has denied wrongdoing.