Three contestants who appeared on ITV's in January and March 1999 were stripped of their winnings after it was revealed they had criminal records.
Neil Muir, Andrew Lavelle, and Sheridan Booth collectively won over £80,000 before their earnings were revoked.
The company behind the quiz show, Celador Productions, confirmed that the trio had falsified their application forms - failing to disclose their criminal pasts.
Under the programme's entry rules, contestants must not have any unspent criminal convictions.
Neil, who won £64,000 in January, was found to have prior convictions for theft, deception, and forgery.
Andrew, who bagged £16,000 in March, was wanted by police over unpaid fines and had a history of driving offences, obstructing the police, and breaching a community service order.
Meanwhile, Sheridan, who won the much smaller sum of £500, had a record for drug offences and burglary.
The decision to strip the contestants of their winnings was made following an internal investigation prompted by public tip-offs.
Executive producer Paul Smith emphasised that the show maintains a strict vetting process and will not tolerate dishonesty.
"We welcome everyone to the show, but anyone with a criminal record will simply not get away with it - they will be found out and their winnings will be withheld," he warned.
Creditors were hot on Neil's heels after his big win on the quiz show, hoping they would be able to cash in on his earnings.
After he spoke about his dream to buy a bit of land in Sierra Leone with his £64k, one fumed: "He'll need that deserted island. It'll give him somewhere to hide from all the people after him. It would be great if he settled all his IOUs. But I'm not holding my breath."
Property manager Mike Snelson was one of the furious men who reported him to ITV, after being shocked that he dared show his face so publicly after leaving him "many thousands out of pocket".
He shared: "I was so shocked when I saw him on TV. It was the first time in nearly three years, but I knew him immediately. The phones have been very hot here ever since."
While Neil kept silent on the matter, Andrew Lavelle spoke out in his own defence, claiming he had every right to his prize money.
He complained: "I'm not a master criminal. If they were not happy they should not have had me on the show."