However the constitutional affairs secretary, who is responsible for elections, insisted that the four all-postal voting trials were "something of a success".

Staff at local councils worked throughout the bank holiday weekend to ensure that voters received their new ballot packs after a series of printing errors.

The government is facing criticism that its decision to ignore the advice of the Electoral Commission and push ahead with all-postal voting pilots for the June 10 elections in four English regions has led to a series of flaws in the system.

Speaking to the BBC Radio 4 Today programme on Tuesday, Lord Falconer reported that all papers had been printed, and 97 per cent were either already distributed or with the Royal Mail.

"In the next 24 hours I am sure they will all be there - that's what I have been advised by officials," he said.

"That will ensure that the ballot papers can go into the system so that people will get them... during the course of this week.

"The vast, vast bulk will be done by midnight.  Some of them may by in the early hours of tomorrow morning.

"But all of that is sufficient for the purposes of getting the ballot papers into the system because the critical thing is that electors have the opportunity to consider their vote and then cast it before June 10."

Candidates in the local and European elections "can forget legal challenges" to the ballot results, he added.

"The scheme is working well. I think we should regard this as something of a success - not, as it were, be carping on the edges."

'Democratic Disgrace'

Liberal Democrat leader Charles Kennedy described the situation as a "democratic disgrace".

"The postal vote situation is a disgrace, a democratic disgrace, no doubt about it," he told GMTV.

"John Prescott, who is the Cabinet minister who has responsibility for this, was publicly warned by the Electoral Commission - the independent body set up by the government to advise on the conduct of elections - and they said do not try out postal ballots in as many regions as four, because there are going to be all kinds of problems potentially."

Conservative spokesman Bernard Jenkin argued that the relative success of the pilots was yet to be discovered.

"The proof of the pudding is whether voters get the right ballot papers at the right time," he said.

"We continue to monitor a grave situation.

"The scramble to meet the June 1 legal deadline has exposed the chaos of these postal pilots, which was entirely inflicted by John Prescott.

"He could have avoided all of this by accepting the advice of the Electoral Commission and every other political party."