Marks & Spencer conducts intensive surveillance of its staff, who live in a culture of fear, according to the whistleblower who was dismissed for contacting The Times.

Tony Goode, a former customer loyalty manager with the retailing chain, broke cover at the TUC conference in Brighton to say that staff were constantly monitored and were afraid to speak out.

Mr Goode, 43, who is a single parent of two, lost his £44,000-a-year job after leaking details of changes to redundancy terms for all Marks & Spencer staff. Mr Goode, who had worked for Marks & Spencer since he was 18, said that he had revealed the information because he had tried and failed to raise concerns with the company and that staff were in fear of redundancies.

The GMB union, which has taken on Mr Goode's case, said that Marks & Spencer had given details of Mr Goode's phone calls to reporters, even though he said that he had made the calls on his personal mobile phone.

However, M&S said that this was “utter nonsense” and that it was impossible to monitor personal phones. A spokesman for the company dismissed Mr Goode's comments as the “lone voice of a disgruntled former employee”.

The GMB said that the store group's headquarters was also heavily monitored by CCTV cameras. M&S said that this was normal practice in a headquarters.

Mr Goode said he could not believe that he had lost his job after 25 years and did not know how he would pay his mortgage or support his 14-year-old son and 20-year-old daughter. “I don't know how I'm going to manage,” he said. “I have a big mortgage and I don't know if I will get another job.”

Mr Goode said that in recent years there had been a dramatic change in a company that used to be a byword for good staff relations. He said: “I've never been a union member before. There was never any need working at Marks & Spencer.”

Mr Goode and the GMB are appealing against his dismissal. If the appeal fails, they will take the retailer to an employment tribunal.

Paul Kenny, the GMB's general secretary, said that staff in the store group felt poorly treated and that unions were beginning to make headway into the organisation. He hit out at M&S's assertion that the GMB was exploiting the case. “That's what we do - we represent workers, we don't sell underpants,” he said.

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