Two referendums for elected regional assemblies have been postponed amid fears about all-postal voting.
Votes in the North West and Yorkshire and the Humber are being delayed. The referendum will proceed as planned in the North East on 4 November.
Ministers say there are no concerns on all-postal votes in the North East but they want to wait for a watchdog's report before deciding on the others.
The Tories say voters have been treated with "utter contempt" in the U-turn.
They say ministers have simply bowed to the complaints of Labour MPs opposed to the assembly plans.
The Electoral Commission is due to report at the end of August on the pilots of all-postal voting in this June's local and European elections.
Ministers had already said they would postpone the votes if the report brought convincing evidence it was not safe to hold the votes.
On Thursday Local Government Minister Nick Raynsford announced that the government was postponing two of the votes without waiting for the watchdog's report.
But he stressed: "Our commitment to referendums in these regions remains unchanged."
Concerns had been raised in Commons debates this week about all-postal votes, he said, and these would be delayed "except where there is a clear expectation and overwhelming support for a referendum".
The North East, seen as the region most likely to vote in favour of the assembly plans, had "consistently welcomed" all-postal ballots, he argued.
Mr Raynsford said he was helping voters in the region by publishing the draft plans for the assemblies' responsibilities and powers.
Ministers would announce in September their reaction to the watchdog's reports and the next steps for votes in the North West and Yorkshire and the Humber.
But Conservative shadow minister Bernard Jenkin said the votes were really being cancelled and Deputy Prime Minister John Prescott had lost his battles for his dream of regional assemblies.
"If an all-postal vote is unsafe in Yorkshire, how can it be safe in Northumberland," asked Mr Jenkin, whose party has opposed the assembly plans.
He asked why traditional polling stations could not be used.
'Lead by example'
"The fact is a majority of Labour MPs were in covert or open rebellion in the North West and Yorkshire this week," he claimed.
He branded the announcement as "absolutely incredible, completely unbelievable and utterly cynical".
Liberal Democrat spokesman Edward Davey, who wants regional assemblies, said: "This is a sad day for democracy, and voters are the real losers."
The hard work already done by "yes" campaigners had been wasted, said Mr Davey.
And claiming the prime minister had tried to stall the assembly plans, he said Mr Prescott was now "not just embarrassed, but severely wounded".
His Lib Dem colleague Andrew Stunnell, MP for Hazel Grove, called on the government to make a clearer statement on the timetable for referendums in the North West and elsewhere.
But Conservative MP for Congleton, Ann Winterton, said the people of Cheshire and Macclesfield were rejoicing at the decision to postpone their referendum.
She urged the minister to "pull the rug from under the stupid proposal" and understand that the idea of regional government in the North West was over.
Labour's Joyce Quinn, MP for Gateshead East and Washington West, said she hoped the North East region would pioneer this new form of devolution.
Campaign for the English Regions chairman Phil Davis said it was a "historic moment" that one referendum would be held in November.
It was sensible to wait for the Electoral Commission's report on problems in the other regions, he said.
But the people of the North East now had "the chance to show the rest of England the difference they can make to the vital issues they face", added Mr Davis.