Breakfast broadcaster GMTV has been fined £2m by media regulator Ofcom for failings with its phone-in quizzes.
GMTV admitted "serious operational errors" with its competitions
Ofcom has handed out the penalty, the highest in its history, because many viewers who entered GMTV's premium-rate competitions had no chance of winning.
For four years, finalists were chosen before lines closed - meaning those who rang later wasted up to £1.80 a call.
In a statement GMTV said it takes "full responsibility" and have "introduced a new code" for premium rate contests.
The show must now broadcast a summary of Ofcom's findings on three separate occasions.
Ofcom said the breaches "constituted a substantial breakdown in the fundamental relationship of trust between a public service broadcaster and its viewers".
It added that the breaches were "extremely serious" as they involved "longstanding and systematic failures in the conduct of broadcast competitions."
The organisation's Tim Suter told BBC News 24 that GMTV was making "a substantial sum of money" from the competitions.
He added that the lack of processes to "deal with people straight and fairly was the most worrying here".
On Monday, the company that ran the contests was fined £250,000 by premium rate phone line regulator Icstis.
Icstis chief executive George Kidd said Opera Telecom "showed a reckless disregard for the interests of callers".
TV SHOWS FINED
Richard and Judy Show, Channel 4 (pictured)
£150,000 for phone-in operator Eckoh after winners were selected before lines closed
£300,000 for faking winners on five occasions
Blue Peter, BBC One
£50,000 for asking a studio guest to pose as the winner of a phone-in
£250,000 for phone-in operator Opera after finalists were selected before lines closed
The scandal has led to the resignations of two GMTV executives - managing director Paul Corley and director of phone-in competitions Kate Fleming.
The problems began in January 2003 and lasted until March 2007, when they were uncovered by the BBC's Panorama programme.
During this period, GMTV's revenues amounted to more than £63 million.
It claimed viewers lost £10m a year, as up to half of all callers never had a chance of winning. GMTV has since admitted "serious operational errors", overhauled its competition system, and terminated its contract with Opera.
The two companies also offered refunds to viewers and set up a series of free prize draws for those affected.
Ofcom noted that the financial penalty would have been higher if GMTV had not introduced an "extensive programme of reparations and remedies".
The regulating body added that GMTV's "disregard for the need to operate any reasonable compliance procedure" was "gross negligence".