Decision demanded over election

Mr Brown is expected to make a decision this weekend

Opposition leaders have challenged the prime minister to end speculation over whether he will call a general election this autumn.

Conservative leader David Cameron called upon Gordon Brown to end what he described as "endless dithering".

Liberal Democrat leader Sir Menzies Campbell said the continued uncertainty was damaging the process of government.

The prime minister is spending the day in Downing Street with his advisors, assessing his decision.

'Dithering and calculating'

Mr Cameron said he and his party were primed for an election if one was called.

Speaking in Oxford, he said: "Gordon Brown has put himself in a fairly extraordinary position. He should either get on and call it or get on with running the country.

"Instead, he's been endlessly dithering and calculating. He's been using government announcements and troop announcements to make himself look good."

In a speech to party members in Glasgow, Mr Campbell said: "All the indications are that the government, both in public and private, has deliberately encouraged the belief that an election is imminent.

Brown would be mad - and he isn't - to let his fate rest on one set of polls BBC political editor Nick Robinson Read Nick's thoughts in full

"That has meant the management of government business has been in the interests of the Labour party, not the public."

He said if given the chance, his party would "rattle the cage" of British politics.

Speculation has been mounting that Mr Brown will call a November election after he announced plans to make a statement to MPs on Iraq on Monday.

An announcement on the government's long-term spending plans has also been brought forward to Tuesday.

The Tories and Lib Dems will spend the day promoting their key policies.

Mr Brown is expected to spend time analysing the latest polling information with his senior advisors.

Private polling

The newspapers on Saturday contain detailed data on surveys of voter views first published on Friday.

Labour is also expected to be looking at private polling carried out in marginal seats.

Mr Cameron has met voters in Oxford, while Sir Menzies addressed his party's Scottish conference in Glasgow.

Speculation has mounted over Mr Brown's intentions since it was announced the government's Comprehensive Spending Review (CSR) - which sets long-term spending plans - and pre-Budget report (PBR) will be brought forward to Tuesday.

This is the last day on which Mr Brown can call an election for 1 November. The two dates most widely touted for an election are 1 and 8 November.

HAVE YOUR SAY Politicians invariably call snap general elections when it suits their own political ambitions Brian Agnew, Preston Send us your comments

The CSR and PBR had been expected later in the month.

Tuesday's CSR - only the second since Labour came to power in 1997 - will set out the government's spending policies and priorities for the next decade or so.

In the pre-Budget report, Chancellor Alistair Darling is thought likely to downgrade the forecast for the growth of the UK economy in 2008.

Falling lead

Recent opinion polls have suggested that Labour's lead over the Conservatives has fallen.

An ICM poll for the Guardian newspaper indicates that Conservative and Labour are level - on 38% - compared with a 7% lead for Labour one month ago.

The poll surveyed 1,008 adults on Wednesday and Thursday, after David Cameron's address to the Conservative conference in Blackpool.

Meanwhile, the results of an earlier YouGov survey for Channel 4 News - which interviewed 1,741 people, also on Wednesday and Thursday - suggested the government, on 40%, was four points ahead of the Tories compared with a lead of 11 points last week.