Downing Street last night promised a careful assessment of all-postal ballots amid allegations of widespread vote-rigging and chaos in yesterday's European and local council elections.

While Leader of the Commons Peter Hain played down claims of voting irregularities in the four English regions where all-postal ballots have been held, a No 10 spokesman said the system would be reviewed in the light of the elections.

"There will be an evaluation to see how the system has worked after the elections," the spokesman said.

In the Commons, Shadow Leader of the House Oliver Heald said that police were now investigating a "whole raft" of complaints.

Mr Heald warned that "fraud, intimidation and sheer incompetence" had marred the all-postal ballots which had taken place in the North-East, Yorkshire and Humberside, the North-West and East Midlands in the first large-scale trial of the system. "We need an urgent statement setting out how the Government intends to address what is now being called the 'fistful of ballots' fiasco," Mr Heald said.

Mr Hain, however, insisted that postal ballots were no more prone to fraud than traditional voting methods and represented "the biggest exercise in spreading democratic opportunity anywhere in Britain and probably anywhere in the world".

Labour MP Bruce George, president of the Parliamentary Assembly of the Organisation for Security and Co-operation in Europe, which monitors elections, called for a full-scale review of the voting system.

"I am not suggesting the whole system is bent," he said. "If there is abuse, it is at the margins.

"But whole elections can be won or lost in a handful of constituencies. We need a root and branch look at our electoral system."

* Tony Blair would not win an overall majority if a General Election was held today, according to a poll last night.

Mr Blair would remain Prime Minister with the largest number of MPs, according to the YouGov survey for Sky News.

But Labour would receive only 32 per cent of the vote compared to the Tories' 36 per cent. The way votes are spread across the country would mean Labour had 327 seats, down 86, and the Tories would be up 91 on 257.

* At 7pm last night there was a 40.26 per cent turn-out for Sunderland, compared to 47 per cent in last year's local elections, which was also all postal but did not require the declaration of identity needed this year.

There was a 52 per cent turn-out for the all-postal elections in Harrogate with some wards such as Ouesburn seeing as many as 62 per cent of people casting their vote.