Programmes such as Coronation Street may be hit by an ITV strike

It was revealed last week that ITV is planning to shut the scheme to its 1,500 contributing members after closing it to new joiners in July.

ITV wants to replace it with one based on career average salaries to help reduce its pension deficit of �325m.

Three unions - Bectu, Amicus and the NUJ - said they would ballot for strike action if the company pressed ahead.

"The company's profits are up and after a significant period of job-shedding through redundancies and outsourcing," said Bectu's assistant general secretary Gerry Morrissey.

"We are prepared to enter into meaningful negotiations with ITV, but we will not rubber-stamp its pension proposals and significantly worsen our members' employment package," he warned.

Any strike action would take place in the New Year.

Takeover

ITV is in the middle of a highly controversial takeover battle.

On Tuesday it turned down a merger proposal from cable TV firm NTL, and last week rival broadcaster BSkyB bought an 18% stake in the company - a move which is to be scrutinised by the regulator Ofcom.

ITV has been struggling to find a new chief executive, four months after the last one, Charles Allen, stepped down.

If the broadcaster closes its current pension scheme to existing members as planned next April, it will be the second company in the FTSE 100 share index, after Rentokil, to take such a step.