The Co-op Group are embroiled in a court battle with a whistleblower who is claiming more than £5 million in damages on the grounds of unfair dismissal.
Kathleen Harmeston, the Co-op Group's former group procurement director, claims that she was unfairly dismissed having made protected, public interest disclosures related to corporate malpractice, including governance issues and breaches of fiduciary duty.
At a tribunal held in Manchester, Ms Harmeston told the hearing that she was "a well known person in the industry for procurement" and had been nominated for Businesswoman of the Year in 2012.
But the tribunal also heard Ms Harmeston left her previous similar role as head of procurement at the Royal Mail while a consultancy firm she used - Silver Lining Partners (SLP) - was under under investigation and had its contract terminated by the postal giant.
There was also dispute over whether her office would be on the sixth floor of the Co-op HQ with her team - or as she wanted on the ninth floor with the most senior executives.
Ms Harmeston had been headhunted by the Co-op Group from her position at the Royal Mail Group she held between 2009 and 2013, having had a 22-successful-year career behind her.
The Co-op had employed her having needed to improve its procurement practice within the crisis-hit business in order to achieve substantial cost savings.
But Ms Harmeston claimed that the Co-op "embarked upon a deliberate campaign to comprehensively disparage my reputation".
In Ms Harmeston's witness statement she said that having taken up the role on April 1 2014, until her dismissal on September 12 2014, she believed she had "at all times acted with the upmost integrity" and had "always acted in the best interests of the respondent".
The statement added: "The respondent's attitude towards me changed in a negative way following the making of those protected disclosures and the respondent initiated a disciplinary process against me, claiming that the trigger for the commencement of that disciplinary process was the receipt by the respondent of an anonymous whistleblowing complaint which I contend contained a number of false statements."
She claims that her suspension from work on June 16 2014, seemed "disproportionate in terms of the nature of the issues presented to me and antithetical with regard to how such allegations and potential issues should be addressed".
She added that her dismissal "could lead one to believe that I had committed some very serious acts or acts" and described it as humiliating.
In the statement Ms Harmeston also claimed she was assigned the secret code name "Wimbledon" so as to avoid "creating a paper trail of emails to me" and thus not being able up submit a data access request under the Data Protection Act.
The statement said: "It is difficult for me to escape the conclusion that the respondent embarked upon a deliberate campaign to comprehensively disparage my reputation with staff, suppliers and within the Executive Search community seeking to neutralise the impact of my disclosures and to utterly destroy my hard won reputation and career."
Ms Harmeston gave evidence on Thursday but Andrew Burns QC, representing the Co-op, focused on another 'whistleblower' involving the witness and her role at the Royal Mail.
It was claimed SLP, who Ms Harmeston had worked with at Royal Mail, were "fleecing" the firm, according to the Royal Mail whistleblower.
Ms Harmeston said it was a "total coincidence" she resigned from Royal Mail while the activities of SLP were being investigated by Royal Mail's auditors and outside security firm, Kroll.
SLP's contract with Royal Mail - its only one, was then terminated.
But the witness agreed she had not told her new employers at the Co-op about the matter and she later re-employed SLP to work at the Co-op, it is alleged without the authority to do so.
Ms Harmeston said there was "no case to answer" against SLP, which she claimed had saved Royal Mail money and described the firm as "competent change agents".
Royal Mail's own investigation concluded SLP did not have the competence to do the work they were asked to.