ITV has been hit with a record £5.67 million fine by Ofcom over a spate of premium rate phone-in scandals, the media regulator has announced.

Ofcom said the record penalty "reflects not only the seriousness of ITV's failures but also their repeated nature".

The regulator investigated after a report found "serious editorial issues" within three ITV programmes - Ant and Dec's Saturday Night Takeaway, Ant and Dec's Gameshow Marathon and Soapstar Superstar.

Today's penalty dwarfs the previous record of £2 million against GMTV, which is 75% owned by ITV. GMTV charged viewers up to £40 million to enter competitions they had no chance of winning.

But ITV could have been fined up to £70 million - 5% of its commercial revenue. The broadcaster made £7.8 million from uncounted votes and some 10 million telephone calls were affected.

City firm Deloitte were called in by ITV to carry out an audit of its programmes and their findings were published in October. It found that in Saturday Night Takeaway, competition entrants for the Jiggy Bank competition were not chosen at random but selected if they lived within an hour of a chosen location and would make good TV.

In Gameshow Marathon, the winner of the "Prize Mountain" of gifts was also not chosen at random, as they were supposed to be, but selected if researchers thought they sounded "lively" and would be more entertaining on screen.

In Soapstar Superstar, votes for celebrities to be put up for eviction were ignored in favour of the production team's choice. On a number of occasions the production team also over-rode the song choices voted for by viewers.

Ant and Dec said they had not been aware of the phone-in scandals, despite being credited as executive producers on Saturday Night Takeaway and Gameshow Marathon.

In December last year, Channel 4 was fined £1.5 million for misconduct involving phone-in competitions on shows Richard And Judy and Deal Or No Deal.