Bosses recruited my secretary to spy on me after I returned from maternity leave

Lenka Sheridan, 32, claims her personal assistant was asked to watch her and report any useful information to directors.

The clandestine operation allegedly took place as her relationship soured with bosses at Alliance Insurance Management.

She claims the company mounted a campaign to oust her after she returned from six months maternity leave, to her £33,000-a-year role as a group finance manager.

The tribunal was told Mrs Sheridan had discussed her future at the company and the problems she was having with her secretary, during the seven months they worked together.

She then discovered an incriminating e-mail between chief executive John McLaren-Stewart and Samantha Thomas, her assistant.

Full details of the e-mail from have not been released, but one line read: "Please ring me about LS."

Mrs Sheridan says the message indicated her assistant had been pretending to be her friend while actually gathering information against her.

Furious at the apparent betrayal, she forwarded the e-mail to every employee in the company - an action she said she regretted immediately and which led to her dismissal for gross misconduct.

She told the tribunal: "I regret sending the e-mail on, but she had been spying on me and passing information to the bosses.

"I probably thought she got what she deserved, but I could have done it on a one-to- one basis. I could not believe that someone who was supposed to be my friend and had comforted me had been gleaning information to pass back."

Mrs Sheridan, who lives with husband Kevin, 38, a painter and decorator, in Sudbury, Suffolk, took maternity leave in January 2006 for the birth of their son Alfie, now 17 months.

She had been working with Alliance, based in Bury St Edmunds, for ten years at the time and "loved" her job.

On her return later that year, however, she alleges the company's attitude towards her changed.

She discovered the person who had replaced her would continue to handle most of her workload, meaning her role had "diminished considerably".

She told the employment tribunal in Bury St Edmunds: "I was unsure of what role was left for me. Stripping me of my responsibilities would not leave much."

She said that over the next month she was made to feel unwelcome and suspected senior management were trying to get rid of her.

The tribunal heard that a possible promotion to finance director which had been discussed before she went on maternity leave was not offered on her return.

An application for flexible working hours was also turned down despite the firm previously saying she would be able to work from home for two days a week.

"The directors could not have made it plainer that I was not welcome back - the company was trying to push me out," she said.

"All the liaising with other directors that I had previously had was now carried out through other people."

"My belief is that this behaviour was carried out not only to exclude me but to make me feel more isolated. I was very much the spare part."

The final straw came when she found the e-mail to her assistant and forwarded it to colleagues, leading to her sacking in December 2006.

Mrs Sheridan is claiming unfair dismissal and sexual discrimination against the firm, which was co-founded by Mr McLaren-Stewart, a former garage mechanic.

She claims her mental health has suffered as a result of her treatment and she has been unable to find work since.

Mr McLaren-Stewart told the hearing Mrs Sheridan had been a valuable member of the team who provided financial reports and was a "major contributor" to board meetings".

But he added: "When she returned after her maternity leave her relations with the directors were strained and uncomfortable. She became confrontational."

The tribunal continues.