Conservative and Liberal Democrat negotiating teams are to meet again within the next 24 hours following more than five and a half hours of discussions in Whitehall, it has been announced.

Shadow foreign secretary William Hague emerged from the Cabinet Office to say that they would be briefing their respective leaders on what he described as "very positive and productive" negotiations.

As the meeting broke up Conservative sources disclosed that David Cameron had spoken again by telephone to Nick Clegg following their 70 minute face-to-face talks in Whitehall.

Mr Hague told reporters that the two negotiating teams - which are discussing possible terms of co-operation in forming a new government - had had a wide-ranging policy discussion.

"We've had some very positive and productive discussions over many key policy areas," he said.

"The issues we have covered have included political reform, economic issues and the reduction of the deficit, banking reform, civil liberties, environmental issues.

"So we've had good discussions about all of those areas. We intend to meet again over the next 24 hours. We are agreed that a central part of any agreement that we make will be economic stability and a reduction of the budget deficit.

"Each negotiating team is now going to report to our party leaders."

While the negotiating teams were meeting it emerged that Mr Clegg met Gordon Brown in the Foreign Office.

Labour and Lib Dem sources said that the meeting followed a telephone call between the two men last night and was intended to update each other on the situation. Both sides described the discussion as "amicable".