Actor Russell Brand, shown last December at the premiere of the film Bedtime Stories, stepped down as a BBC talk-show host. (Dan Steinberg/Associated Press)

Britain's broadcast regulator has levied a record fine against the BBC over lewd prank calls made last October by talk show host Jonathan Ross and comedian Russell Brand.

The incident also led to the resignations of former talk-show host Brand and two senior BBC executives. Ross earned a suspension.

The Office of Communications, or Ofcom, ordered the BBC to pay a £150,000 ($274,000 Cdn) fine over the incident, the largest ever imposed against a broadcaster.

The prank calls to actor Andrew Sachs, made on Brand's radio program, joked about Brand having sex with the actor's granddaughter and a followup program referred to the incident.

Thousands of complaints were registered with Ofcom after the BBC Radio 2 programs aired.

Ofcom called the calls "gratuitously offensive, humiliating and demeaning" as well as a serious breach of privacy. It said such pranks should only be performed with the permission of the subjects.

The regulator found senior managers at fault for failing to listen to the broadcast in its entirety ahead of time, saying Brand's show was "high risk" because its humour frequently pressed the boundaries of good taste.

It levied a £70,000 fine for breaching rules on offensive material and an £80,000 fine for failing to protect the privacy of the individuals being pranked.

British MP Jeremy Hunt called the incident a breach of trust for the public broadcaster, in part because BBC is financed by the British taxpayer.

The BBC issued an apology for the incident on Friday.

"As we said last October, this material should never have been broadcast and we apologized unreservedly for that. The BBC has since taken comprehensive action to deal with what were unacceptable failures in editorial judgment and compliance which led to the broadcast," it said in a statement.

It was the second such apology — the broadcaster also issued a mea culpa immediately after the incident.

With files from the Associated Press