Ofcom said a fine of this sum was imposed “given the seriousness and repeated nature of this breach” of its broadcasting code.
In a statement, Ofcom also said it has told GB News it will be required to broadcast a statement on the watchdog’s findings, at a date of their choosing.
Ofcom also noted GB News’ current legal challenge against Ofcom, which is over a number of rulings.
Mr Frangopoulos called the financial sanctions “unnecessary, unfair and unlawful”.
“The plan to sanction GB News flies in the face of Ofcom’s duty to act fairly, lawfully and proportionately to safeguard free speech, particularly political speech and on matters of public interest,” he said.
GB News has already lost a High Court challenge to stop Ofcom from temporarily sanctioning it, in which their lawyers argued it would cause “irreparable damage” to its reputation.