The premium rate phone-in scandals have rocked TV companies’ income, with a drop in callers of at least 43 per cent.

A survey found that 43 per cent of those who took part in ‘participation TV’ in the last 12 months have now stopped.

Nearly two thirds (63 per cent) no longer take part or have significantly reduced their involvement.

Spending on TV votes, programme quiz questions and dedicated quiz channels has plummeted from £400 million at the height of its popularity to around £120 million in the last 12 months.

Most of the decline took place in the past four months.

The report, Battling For The Media Consumer – Winners and Losers, says: “Until this summer, participation TV was the golden goose for free to air television networks which had seen their traditional advertising revenue come under pressure from a growth in rival channels and the PVR (personal video recorder) threat to spot advertising.

“Commercial network broadcasters will clearly have to look elsewhere for revenue growth in the future.”

A separate report by management consultancy Mott MacDonald Schema found 89 per cent of people who have used premium-rate phone-in services have lost confidence in them.

Oliver and Ohlbaum questioned 2,500 adults in the UK. Mott MacDonald Schema commissioned Ipsos Mori to interview a nationally representative sample of 900 British adults.

On Wednesday GMTV was fined £2 million by broadcasting watchdog Ofcom for charging viewers to enter competitions they couldn’t win.