UNISON staff insisted yesterday that they stayed above board during last year’s general secretary election.

An official hearing on the conduct of the public-sector union’s 2015 vote adjourned yesterday after three days.

Long-standing leader Dave Prentis was re-elected but all three of his rivals complained to the Certification Officer.

The plaintiffs’ representatives told the hearing that senior officials charged with running the election were part of Mr Prentis’s campaign team.

One official, Liane Venner, liaised directly with ballot administrators Electoral Reform Services but was also present at a meeting to discuss Mr Prentis standing again, and later received “Team Dave” emails.

But she told the hearing she had not read many of the emails and said: “I took a decision not to take an active role in the campaign.”

The union’s relationship with the ballot administrators has come under scrutiny. The defeated candidates have accused officials of applying pressure to ERS after disagreeing with guidance issued by the company about election rules.

The court heard that Team Dave emails, which were later anonymously leaked to election runner-up Heather Wakefield, were sent from assistant general secretary Cliff Williams’s personal email address.

These encouraged fellow officials to “piggyback” on “official meetings” — with the caveat that this should be done “outside the Unison day.”

The plaintiffs’ legal team argued that Mr Williams’s suggestions had been taken up by then London region secretary Linda Perks, who was suspended after revelations she briefed regional staff on campaigning for Mr Prentis.

Mr Williams said her activities were separate, saying: “Ms Perks tried to present it as within the flexible working arrangements, but it seemed it was in the working day.”

He also said a “Chinese wall” had existed between him and the union while he acted as Team Dave campaign chief.

After a fourth hearing day in the new year, assistant certification officer Mary Stacey will decide whether to uphold the complaints and whether to take out an “enforcement order.”