A judge investigating vote-rigging in Birmingham's local elections has ruled there was widespread fraud and has ordered new elections.
The councillors deny the allegations
Election Commissioner Richard Mawrey QC upheld allegations of postal fraud relating to six seats won by Labour in the ballot of 10 June last year.
The results have been declared void and the polls in two wards must be rerun.
"The system is wide open to fraud and any would-be political fraudster knows that," Judge Mawrey said.
Judge Mawrey said evidence of "massive, systematic and organised fraud" in the campaign had made a mockery of the election and ruled that not less than 1,500 votes had been cast fraudulently in the city.
The deputy high court judge said the system was "hopelessly insecure" and expressed regret that recent warnings about the failings had been dismissed by the government as "scaremongering".
He criticised the government's insistence that the current postal voting system was working, adding: "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."
Mr Mawrey had heard petitions lodged against six Labour councillors, who all strenuously deny that they abused the postal ballot system.
The first petition was brought by the People's Justice Party (PJP) against three representatives of the Bordesley Green ward, Shafaq Ahmed, Shah Jahan and Ayaz Khan.
They walked out of last month's hearing on the first day after Judge Mawrey refused an application for an adjournment to allow them further time to prepare their case.
The second petition was raised by Liberal Democrat supporters against three Aston representatives, Mohammed Islam, Muhammed Afzal and Mohammed Kazi.
During the hearings, which were held at the Birmingham and Midland Institute and lasted four weeks, Judge Mawrey heard how the trio were caught operating a "vote-rigging factory".
The police described how they found Mr Islam, Mr Afzal and Mr Kazi handling unsealed postal ballots in a deserted warehouse in the city.
The Aston councillors were found counting votes at a warehouse
The petitioners also accused the city's returning officer and chief executive Lin Homer of failing to discharge her duties in accordance with electoral law.
Judge Mawrey said that Ms Homer "threw the rule book out of the window" to deal with overwhelming numbers of postal vote application forms received.
Solicitor Chaman Salhan, who represents two of the councillors, said the men had not been given enough time to prepare their defence.
"They are victims of circumstance - in effect we have had a criminal trial under civil procedures," Mr Salhan said.
West Midlands Police told BBC News that they were currently not pursuing a criminal inquiry.
A spokesman for the force said: "We will review the judgement and see if any issues need to be addressed. Nothing relating to the case is in progress at the moment."
Speaking outside court, a spokesman for the People's Justice Party called for postal voting to be outlawed at the general election.
"The commissioner has confirmed our fear that there is every likelihood that the forthcoming general election will be blighted by postal vote fraud," he said.
The Electoral Reform Society said urgent action was needed to protect and maintain confidence in the voting system.
Mr Mawrey ordered that none of the six councillors be allowed to stand for the vacant seats at the next election.