Three Labour councillors accused of vote-rigging in last year's local council elections in Birmingham, have walked out of a High Court inquiry.
The hearings are being viewed as test cases after other complaints
Shafaq Ahmed, Shah Jahan, and Ayaz Khan, left just before the start of the hearing, the first of its kind in England in living memory.
Six Labour councillors are accused of collecting postal votes fraudulently.
The men, who represent the Aston and Bordesley Green, wards all deny rigging ballots and being improperly elected.
Deputy judge Richard Mawrey QC, expressed regret at the councillors' decision to walk out, but acknowledged that the trio could not be forced to attend or to give evidence.
They left the hearing with their solicitor after the judge rejected an application for an adjournment to allow them further time to prepare their case.
The High Court has appointed a judge as Election Commissioner for two separate hearings, covering Aston and Bordesley Green, which are expected to last four weeks in total.
Judge Mawrey told the court on Monday that the matter must be dealt with before a possible General Election in May.
He said if allegations of fraud were proved correct, then the system was "wide open to serious and massive fraud".
Birmingham was not part of the postal-only experiment, but the hearings are being viewed as test cases following complaints about irregularities in other parts of England and Wales.
'Forgery and deception'
The case against the three Bordesley Green representatives - Shafaq Ahmed, Shah Jahan and Ayaz Khan - has been brought by the pro-Kashmir People's Justice Party.
Local Liberal Democrats have petitioned against the three Aston councillors - Muhammad Afzal, Mohammed Islam and Mohammed Kazi.
Both petitioning parties claim local Labour activists used forgery and deception to collect votes.
Opening the case against the accused on Monday, barrister Graham Brodie said up to 1,500 postal votes in Bordesley Green had been cast with signatures on the actual ballot paper which differed from those on the original application form.
He also identified 15 categories of evidence, covering various methods of alleged fraud and malpractice.
The categories included forged signatures on witness declarations, and votes with "startlingly similar" signatures on both the ballot slip and that signed by a witness.
Another category comprised papers on which the signatures of more than one voter were identical.
It was also alleged that other ballots had been "physically altered" in favour of Labour Party candidates.
The hearing was told that correction fluid had been used on one form and evidence would be presented to the inquiry that some members of the electorate only discovered they had been registered for a postal vote when they turned up at polling stations.
Mr Brodie told the judge: "Postal votes were cast in the name of people who never applied for them.
"Some actually attended at polling booths and were simply told, to their amazement, that an application had been made in their names for a postal vote."
Mr Brodie stressed that the Returning Officer at the elections was not in any way party to any of the "illegal" conduct, but he did claim that there had been failures in the voting system.
The case continues.