The NASUWT teaching union has admitted breaching union law by allowing its general secretary to overstay her term of office.

Russ Walters, the union’s honorary treasurer, told a hearing of the Certification Officer in London this morning that the union believed “incorrectly” that Keates was entitled to serve for an additional six months because she was due to retire.

The hearing was called following a complaint by Susan Parlour, the union’s former Northern Ireland president and a former executive member, that union law was breached when Keates continued in her post beyond June 3 of this year, the anniversary of her election in 2014.

Union law states that union general secretaries must seek re-election every five years.

Giving evidence on behalf of the union today, Walters said national officers at the union believed they could allow Keates to serve for an additional six months based on an old rule that no longer exists in statute.

“I think it’s been long understood – it turns out incorrectly – that when somebody was retiring from work they were in a different position than when they were simply leaving to go to another job,” he said.

“I think I’ve been as honest as possible and the union has been honest that we accept we were wrong in that viewpoint.”

NASUWT insists Keates is now serving as acting general secretary, an interim position she will hold until her successor is chosen.

But Parlour, who was debarred from national office by the union earlier this year after she questioned the lengthy suspensions of union officials, told the hearing she believed Keates continued to serve.

“I think she has rebranded herself. She’s still doing the same job, she’s carrying out it the same functions. My belief is she has simply relabelled herself.

“If there’s an acting position, that is someone who comes in to step up.”

Asked when Keates’s replacement would be in place, Walters said: “The answer is how long is a piece of string.

“I can’t determine who the candidate will be at this time, therefore I can’t determine how long the transition will be.”

The hearing continues.