Millions of people hoping to watch the Queen's diamond jubilee celebrations in June may be disappointed because of a pay dispute at the BBC.
Producers, technicians and presenters have threatened to strike over a 1 percent pay rise offer by the management.
Results of the strike ballot of members of the National Union of Journalists (NUJ) and Bectu will be published by 21 May. The jubilee celebrations run from June 2-5.
The offer, which would see a minimum increase of £400, prompted the ballot for industrial action, said Gerry Morrissey, Bectu general secretary said.
"Action over the Queen's diamond jubilee weekend is extremely regrettable, but this offer is derisory," the BBC quoted Morrissey as saying.
BBC management said it would not budge on the offer.
Morrissey said: "We have no option but to call a strike ballot at the earliest," he said on the union's website.
The BBC maintained that it had implemented the pay rise earlier than normal.
"We are very disappointed that the unions have decided to ballot their members about taking industrial action. The economic climate remains tough for everyone and this action will not change our circumstances," said a BBC spokesman.
The unions are demanding 2 percent over and above inflation, with a minimum increase of £1,000.
Michelle Stanistreet, general secretary of the National Union of Journalists, said BBC management had failed to negotiate on a range of issues, including a redeployment scheme for staff.
"This has left us with members needlessly facing compulsory redundancy. There are jobs these members could go to, but the BBC is failing to fulfil its part of the bargain," said Stanistreet.