The company responsible for the 'You Say, We Pay' phone-in competition on Channel 4's 'Richard and Judy' show has been fined a record £150,000.
Premium rate phone watchdog ICSTIS also ordered Eckoh UK Ltd to provide refunds to all affected viewers.
ICSTIS ruled that the competition seriously misled viewers after they were asked to ring into a £1-per-go quiz despite the fact that winners had already been chosen.
Sir Alistair Graham, chairman of ICSTIS, said: "The size of the fine reflects the very serious nature of the breach of our Code of Practice."
"Winners were being chosen before the competition closing deadline, whilst millions of additional viewers were still encouraged to phone in and pay to enter competition but were denied the opportunity of fair consideration."
"Such reckless disregard for viewers is unacceptable."
The incident happened, ICSTIS said, "as a result of serious errors and fundamental failings".
ICSTIS referred the case to broadcasting regulator Ofcom, which has now launched an investigation into Channel 4.
