The insider said that of the 14 presiding judges, eight or nine would likely vote to nullify the election while five or six were determined to cast dissenting votes.

The source said fiery debates had centred on four key legal issues: the scheduling of the election, whether the configuration of balloting booths violated voter privacy, the alleged bankrolling of small parties by the government and the lack of a formal review of ballot results.

The judges spent most of their time examining evidence related to the ballot booths, the source said.

They were reportedly split on the matter.

Those who approved of the configuration of the booths argued that as the voters had their backs to bystanders no one could have seen how they were voting.

They also argued that all local elections had proceeded without protest or complaints of ballot confidentiality violations and even other countries, including Australia and Japan, have used a similar configuration for their ballot booths.

But the majority of the judges believed voters could not have cast their ballots with confidence that no one could see how they voted.

And that constitutes a breach of the law, specifically Article 104 of the charter.

The source said the election would be nullified by the verdict and other ongoing law suits related to the election outcome, which are threatening to bog down the administrative courts, will be automatically rendered void, because the Constitution Court takes precedence over all others.

The source said he was confident the ruling would end the political crisis.