The industrial tribunal into claims of harassment and discrimination against Goan workers at the Great Western Hospital, heard from its final witness on Friday.

Gemma Lynch, Carillion’s facilities general manager at the hospital, had conducted an investigation into individual complaints by Goan workers about some of their supervisors.

She admitted to the tribunal that her theory was that Carillion staff who had joined the GMB union had hatched a plot to oust supervisor Christine Woods by accusing her of harassment, racism and bribery.

After her junior colleague Gary McAllister had conducted an investigation into collective grievances about Ms Woods and others, she had interviewed more than 50 staff each with an average of five personal grievances.

The process had taken “thousands of hours”, she said, but she had not upheld a single grievance. Instead some Goan workers were recommended for disciplinary action.

“Wasn't that utterly remarkable?” commented Oliver Segal QC for the GMB, pointing out that Mr McAllister had reached very different conclusions in a report produced some months earlier.

“I found it hard to believe that they found Christine Woods frightening,” she explained.

Mr Segal went on to point out that Ms Woods had already been persuaded to resign from Carillon by Mrs Lynch before Goan staff had named her in their individual grievances. They had been too frightened to name her while she was still on the premises, so that put paid to Mrs Lynch’s theory.

“Do you accept that you think the GMB had persuaded people to give false evidence to Mr McAllister and to the tribunal?,” he asked, drawing attention to the fact that she knew not all the complainants were GMB members.

“There was a perception then and now that people were putting forward things they did not know about or believe,” she said.

“Whether it was true or not about the bribery claims, I did find some of the timings puzzling. They didn't make sense.”

Mrs Lynch, who is now Carillon's Operations Manager for new Government Services, was challenged about the evidence she had given to the preliminary tribunal hearing in January 2015.

Why had she not revealed the existence of the extensive report produced by Mr McAllister which contained detailed evidence supporting the claims being made by the GMB, asked Mr Segal, adding “The way you contrived to cover it up was masterful, but misleading”.

She was acting on advice from Carillion’s lawyers, she explained, but she didn’t think it was relevant. She agreed that the report contained very serious allegations against Christine Woods and others, and not for the first time, and that Mr McAllister had guaranteed confidentiality to Goan staff.

Had he not told her that GMB officials had been scrupulous in persuading people to tell the truth when they were reluctant to talk, asked Mr Segal. “Yes, not in so many words,” she replied.

She was asked to explain why later she recommended that the same people should face disciplinary action.

“They had not been offered immunity and they had admitted offering gifts for personal advancement,” she said, but no action had been taken against them.

The presiding judge intervened to say “That sounds like a classic ‘magistrate's fudge’. When heavy sanctions are not applied it suggests someone has been found guilty but not very guilty. You found them guilty but not very guilty?”

“Well, yes,” said Mrs Lynch.

“I am sure Mr Segal will explore this further on Monday,” said Judge Livesey, bringing the proceedings to a close.