Ofcom has levied a fine of £1.5 million on Channel 4 over irregularities in two premium-rate phone-in competitions.
The media regulator fined the broadcaster £1 million for the early selection of competition finalists on the You Say, We Pay section of the Richard and Judy show, while the staggered selection of contestants on Deal or No Deal led to a £500,000 penalty.
Channel 4 will also be required to screen two apologies over both fines on three separate occasions.
In response the broadcaster said it fully accepted Ofcom's ruling and apologised again to affected consumers.
The You Say, We Pay organiser has already been fined £150,000 after a premium-rate phoneline number was displayed despite contestants already being chosen on programmes broadcast between September 2004 and February 2007.
And the fine for the Noel Edmonds-hosted Deal or No Deal relates to a staggered selection that gave early entrants a greater chance of winning.
Channel 4 says it plans to donate £900,000 to the Great Ormond Street Hospital children's charity in addition to paying Ofcom's fines.
The broadcaster explained this figure represents the profit made on some 2.9 million calls received but not entered in You Say, We Pay competitions.
Anne Bulford, Channel 4's finance director, accepted that it was the channel's ultimate responsibility to ensure the competitions were run "fairly and transparently".
"There was absolutely no intention on Channel 4's part to mislead our viewers and we are pleased that the regulator has acknowledged our extensive efforts to make reparations since the problems came to light."
Ms Bulford added that she hoped Ofcom's ruling had brought the affair to a close.
"We would like to apologise once again to those affected and to assure all our viewers that Channel 4 is committed to applying the lessons learned across all its activities and to doing everything in its power to regain and maintain their trust."