The government has predicted that voters will receive their postal ballot papers by tonight's Midnight deadline, after council workers worked throughtout the bank holiday weekend to ensure their distribution.

"Regional returning officers report a total of 91 per cent of ballot papers have been printed and either issued to the Royal Mail or are due for collection," said constitutional affairs minister Chris Leslie.

"All ballot packs are on course to be issued by Midnight, following round-the-clock printing over the weekend."

However, opposition parties have expressed their concern that some voters in the four regions piloting all-postal voting may be disenfranchised by what Leslie described as "glitches".

"The proof of the pudding is whether voters get the right ballot papers at the right time," said Conservative local government spokesman Bernard Jenkin.

"The scramble to meet the June 1 legal deadline has exposed the chaos of these postal pilots."