Lance Bombardier Kerry Fletcher, 31, claimed she was pestered for sex by the unnamed sergeant.

Miss Fletcher told an employment tribunal in Leeds that the staff sergeant began to send her text messages indicating he wanted to have sex with her while she was working at an Army stables in North Yorkshire.

She said the sergeant and other male colleagues tried to destroy her career because she spurned his advances and claimed she was signed off sick with stress as a result.

It was reported she could be in line for as much as £400,000 in compensation after winning her claim.

The tribunal heard the sergeant asked Miss Fletcher to join in a threesome with another woman and boasted in a text message: "Look, I might be able to convert you. You don't know what you are missing."

The senior NCO told the tribunal he did not send any message like this to her. He said he maintained his innocence despite an Army inquiry finding it was probable he did send explicit text messages and a colonel handing him an "expression of severe displeasure" after deciding not to demote him.

The staff sergeant said Miss Fletcher was often late for duties and insubordinate towards him. He said that after a period of leave he decided "enough was enough" and decided to enforce discipline more severely.

He denied he had singled her out for more severe treatment because she had rejected his sexual advances.

Miss Fletcher, who has been in the Army for 10 years, lives in Birmingham but is originally from Sheffield.