All-postal voting should not be used in UK elections, a key watchdog has said after reviewing trials in June's local and European polls.
All-postal ballots have been dogged by fraud allegations
The Electoral Commission says it is too early to say whether increased use of postal voting has caused more fraud.
But, it says, the trials involving 14m people were hit by problems including delays in delivering voting papers.
The government says it will consider the report carefully. The Lib Dems said the report was "hugely embarrassing".
The government has already postponed regional assembly referendums in the North West and Yorkshire and the Humber amid fears on all-postal voting.
The commission says it is too late to stop the North East's regional referendum this autumn being an all-postal vote.
That conclusion was welcomed by ministers but the Conservatives and campaigners against the assembly vote want the vote postponed.
All-postal voting trials were held this summer in the North East, North West, East Midlands and Yorkshire and the Humber in elections in England.
Turnout was 5% higher in those regions than in those areas using polling stations.
The watchdog says there was a successful set of elections but logistical problems and complaints it was too complicated to cast a postal vote hit public confidence in the trials.
Commission chairman Sam Younger told BBC Radio 4's Today programme: "Voters are saying very clearly that they want a choice to whether they go to a polling station or whether they vote by post.
"They didn't like being forced to vote by post."
A clutch of claims of voting abuse in the June elections have been lodged with the High Court in London.
But the watchdog says it knows of only two claims that have resulted in arrests and returning officers have found no evidence of fraud or irregularities.
But with many polling officers still doing checks, it says it cannot yet say whether increased postal voting has raised fraud or malpractice.
Among fears about all-postal voting is that it allows people to be intimidated at home, away from the secrecy of the conventional ballot box.
The North East vote should still go ahead, says the watchdog
The commission points to claims there is a particular risk dominant householders could influence how their families vote in some ethnic minority communities.
It plans to talk to the Campaign for Racial Equality about how to improve understanding of voting activity in ethnic minority communities.
Postal voting and other options should be alternatives to polling stations, says the commission, but new measures to ensure security should include:
- Urgent reform of Britain's "archaic" voting laws, with special provisions on security and secrecy
- New laws to update the offence of "undue influence" in elections and a new offence of fraudulent completion of postal votes
- Getting voters to register individually, not by household, and replacing the witness signature for postal ballots with a new security statement
Local government minister Nick Raynsford said the commission's view there should be a range of options "entirely fits with the government's policy".
The government pushed ahead with the all-postal pilots in four regions in June - when the commission said it should only be done in three.
But Mr Raynsford said the move had been aimed at boosting turnout.
Logistical problems had stemmed delays caused when opposition parties disputed where the pilots should be held, he argued.
Conservative local government spokeswoman Caroline Spelman said: "The report is basically a vote of no confidence in the government decision to ram through changes forcing postal voting on voters."
And Liberal Democrat chief executive Lord Rennard branded the findings "embarrassing" for ministers.
"They were warned in advance of the June elections that they should not try to tinker with voting systems for party advantage," he said.
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