Some BBC staff protested about the plans on Wednesday

Bectu, NUJ and Unite representatives said plans to close 2,500 posts and make up to 1,800 staff redundant would "undermine quality programming".

NUJ general secretary Jeremy Dear said the BBC "must withdraw these plans, agree a framework for negotiations or face the potential of strike action".

It followed the announcement of plans to reduce the size of the corporation.

BBC TV audiences can expect more repeats and fewer original programmes under plans revealed on Thursday.

Mr Thompson said the plans involved "difficult choices" Thompson's key points

The majority of redundancies will come in news, programme-making and regional centres.

The BBC will also sell off its flagship Television Centre in west London as it attempts to make up a �2bn budget shortfall.

The corporation has plans in place to ask staff to volunteer for redundancy. The unions say they will ballot for industrial action if the BBC refuses to suspend the redundancy exercise.

They have given BBC management until 1200 BST on Friday to respond.

Budget cuts

Earlier on Thursday, BBC director general Mark Thompson said his plan would deliver "a smaller, but fitter, BBC" in the digital age.

THE EDITORS' BLOG Our audiences are changing and we must change with them Helen Boaden, director of BBC News Helen's comments in full

The six-year scheme, called Delivering Creative Future, was prompted by a smaller than expected licence-fee settlement from the government.

Every part of the BBC will be required to make efficiency savings.

The main changes include:

Across TV as a whole, the BBC plans to commission 10% fewer hours, saving �100m every year.

Despite press speculation, digital channels BBC Three and BBC Four will remain.

HAVE YOUR SAY More repeats are fine so long as you show programmes people want to see again Paul Tapner, Poole, UK Send us your comments

Up to 370 people will be made redundant in BBC News by 2012, but the process is expected to be pushed through "as fast as possible".

Mr Thompson told staff: "BBC News is, and will remain, the cornerstone of the whole organisation. The proportion of content spend that goes to News will go up not down over the coming years."

Plans for BBC journalism include an enhanced on-demand news, sport and local information for the digital age.

There are also plans to build content for younger audiences, including a multi-media Radio 1 Newsbeat.

BBC NET REDUNDANCIES BY DEPARTMENT