The judge in a vote-rigging trial says the postal voting system is "wide open to fraud" and has strongly attacked the government's attitude to the problem.
The hearings were seen as a test case over postal voting
Richard Mawrey QC was speaking as he ruled there had been "widespread fraud" in six Birmingham council seats won last year by Labour.
He accused the government of being not only complacent, but "in denial", about the failings of the system.
More people than ever are preparing to vote by post in the general election.
'Steal me' envelopes
Postal voting was available on general demand for the first time in 2001, when 3.9% voted by post.
About 15% of voters have asked for postal ballots for the poll expected on 5 May.
Acting as an election commissioner, Mr Mawrey called the system "hopelessly insecure".
He was worried election officers could not check the validity signatures on returned ballots.
It did not help that the ballot envelopes were easily identifiable in the post, he said.
"Short of writing 'Steal Me' on the envelopes, it is hard to see what more could be done to ensure their coming into the wrong hands," Mr Mawrey added.
The judge said he regretted the government had dismissed recent warnings about the system's failings as "scaremongering".
He pointed to a government statement which said: "The systems already in place to deal with the allegations of electoral fraud are clearly working."
Mr Mawrey said: "Anybody who has sat through the case I have just tried and listened to evidence of electoral fraud that would disgrace a banana republic would find this statement surprising...
"The systems to deal with fraud are not working well," he said.
"They are not working badly. The fact is that there are no systems to deal realistically with fraud and there never have been. Until there are, fraud will continue unabated."
Birmingham was not part of the postal-only experiment undertaken in some areas at the last local elections.
Both the pro-Kashmir People's Justice Party (PJP) and the Liberal Democrats claimed local Labour activists used forgery and deception to collect votes - something the candidates denied.
The Electoral Commission said the case raised serious issues on the system generally.
It wants changes and hopes the government will legislate as soon as possible.
"Whilst these changes could not now be made in time for the general election expected in May, the commission has been working with others on a number of measures," said a spokesman.
The commission has drawn up guidelines for candidates on how they should handle postal voting inquiries and is working with police chiefs on advice for their officers.
A spokesman said there had been widespread postal voting since 2001 and many people appreciated the extra convenience it brought.
In a statement, the Labour Party said it would consider the issues raised by the judgment.
It said the highest standards of integrity and honesty it expected from its councillors and campaign workers had not been met.
The six councillors and the Aston ward organiser were to be immediately suspended pending the completion of a "vigorous disciplinary process", it added.
Lib Dem president Simon Hughes said election laws needed changing and police had to investigate cases rigorously.
"The Electoral Commission must now take action to ensure that people are aware of how to protect their votes from theft," he said.
The Conservatives say the way postal voting was introduced has caused widespread concern about its integrity.
Tory co-chairman Liam Fox said: "The country that exported democracy to the world must not become victim to the practices of developing countries."
And a PJP spokesman said: "The commissioner has confirmed our fear that there is every likelihood that the forthcoming general election will be blighted by postal vote fraud."