Strike dates threaten to derail BBC coverage of key political events

Unions representing thousands of BBC staff announced four days of strikes last night, intended to cause disruption to the Corporation's coverage of next month's Conservative party conference and the public sector spending review two weeks later.

In an attempt to avert the industrial action, Mark Thompson, the director-general of the BBC, will address the organisation's staff on Thursday to argue the case for accepting concessions he has made over proposed changes to the BBC pension scheme.

Earlier this month, BBC members of the Bectu, NUJ and Unite unions voted emphatically for strike action over a proposed cap on the BBC pension, which is designed to plug a deficit of £1.5bn in the Corporation's pension fund. The BBC responded with an alternative proposal, which was discussed by union leaders yesterday.

The leaders emerged from their meeting to formally name strike dates on 5 and 6 October, during the Conservative party conference in Birmingham, and on 19 and 20 October, to coincide with the announcement of the public sector spending review. But the unions said that the strikes would not be implemented until after a further round of consultation with members that will commence on 20 September and last for 10 days. Union leaders will meet on 1 October to approve strike action, unless members show support for Mr Thompson's concessions.

Under the initial BBC proposals, those members of the 19,000-strong Corporation staff wishing to remain in the final salary scheme would have had future salary increases for calculating pension benefits capped at 1 per cent annually. The plan caused fury, especially as it coincided with news that the 15 most senior executives at the BBC were paid £4.76m last year, up from £4.6m the year before.

The key concession made by the director-general is a new career-averaged benefits option – known as CAB 2011 – which would be offered to existing BBC pension scheme members. Under CAB 2011, pension benefits would be based on an employee's average pay from the time they took up the option to the time of their departure from the BBC.

The BBC will undertake a charm offensive that will begin on Thursday with a speech and Q&A session from the director-general which will be relayed by video-link to the Corporation's offices around the country. On 20 September – the same day that the unions start canvassing their members on Mr Thompson's concessions – BBC executives will visit regional offices to try to head off industrial action by winning support for the director-general's proposals.

As a result of these discussions, union plans to stage industrial action on 20 and 21 September, during the Liberal Democrat conference in Liverpool, have been called off.

Gerry Morrissey, general secretary of Bectu, said management and unions were still some way apart. "Whilst the BBC has heard and responded to some of our concerns, we are disappointed that the BBC's response fails to take account of the long-term implications of the worsening of pension terms for staff and their families," he said.

"We believe the BBC should be prepared to justify its position fully by agreeing to revisit pension benefits in April 2011 should official figures confirm the total scheme deficit is less than £1.5bn. That said, the latest proposals from the BBC warrant further detailed examination with members."