The BBC's director general last night refused to reopen talks with the National Union of Journalists as the row over pensions threatened to take strike action into Christmas and the New Year.
Mark Thompson said in an email to staff that the corporation had reached its "final position" and could not contemplate changes to new pension arrangements which have been accepted by four out of five unions representing the corporation's staff.
TV and radio programmes were disrupted on Friday and Saturday because of a 48-hour walkout by thousands of members of the National Union of Journalists, with another 48-hour stoppage planned to start a week today.
The union has raised the threat of disruption to programmes over Christmas and the New Year unless there is a breakthrough in the deadlocked row.
NUJ general secretary Jeremy Dear today offered to suspend industrial action if BBC management agreed to negotiate a deal once the state of the pension fund deficit was properly assessed next year.
The BBC has made changes to pensions on the basis that the deficit is at least £1.5 billion, but unions believe it could be much lower than this.
Dear said: "Next year we will all finally know what the actual deficit is, rather than an inflated 'guesstimate'."
But Thompson said in his email: "The NUJ have begun a work-to-rule this week and have a second 48-hour strike planned for next week.
'We are putting in place plans to handle both of these and will seek, if possible, to offer the public programmes and services from the BBC with even less disruption than last week.
"That will be the case however many strikes there are. As I said to you in my email last week, we have already reached a final position with four out of five of the BBC unions.
'We cannot and will not enter fresh negotiations or contemplate fresh changes to the agreed offer on pension reform no matter how much industrial action there is from the NUJ.
"The staff consultation on the BBC's pension proposal ends on November 15. As you know, we made significant changes to our original pension proposals as a result of what you told us and the agreement we reached with the unions reflected many of the concerns you raised.
"Nothing has been thrown up in the latter stages of the consultation that would cause us to make any substantive or economically significant changes to the package, but there are a few areas where you would like clarification on the detail of the proposals. Once the consultation closes we hope to offer you that clarity by writing to both staff and unions to set out our detailed implementation plans."
Dear said: "We're determined to achieve a pensions settlement which is fair, but the only way we can know what is fair is by knowing exactly how big the pensions fund deficit is.
'The BBC have variously claimed that it's £2 billion, or £1.5 billion, or somewhere in between.
"We're saying that in advance of the deficit being properly assessed and us all finally knowing the actual size of the deficit, the BBC should not impose changes now. The pension fund's regular, scheduled assessment is due early next year.
"If the BBC agrees to reopen negotiations should the deficit turn out to be less than £1.5 billion and make it clear that in the meantime, any changes currently planned would not have an actual impact on any individual's pension entitlement before we know the true size of the deficit, we will suspend industrial action immediately."