A tracking device was secretly fitted to a Denholme Gate mum’s car by private investigators brought in by West Yorkshire fire chiefs to discover whether she was moonlighting while on sick leave from her job as a 999 call handler.

Anthea Orchard, 35, said she and her family were horrified when she discovered the device, and has now questioned whether public money should be used in such a way.

Mother-of-two Mrs Orchard was signed off work by a doctor after she fell ill with stress and hyper thyroidism last November, shortly after returning from a year-long maternity leave.

Almost immediately, the fire service employed a private investigator to spy on her after her bosses suspected she was working full-time running a business from her hobby of balloon making.

Mrs Orchard said shortly after her sick leave started, odd phone calls were made to the family home by people asking if she could do some work for them; her family and neighbours saw men hiding in cars outside her home, and then she found a GPS tracker had been attached to the underside of her Audi car.

Mrs Orchard, who lives with her husband, Gareth, five-year-old daughter, Ashleigh, and Haydn, now two, said: “I was getting phone calls from people trying to get me to take on work.

“I’d told them I couldn’t because I was signed off work. The number hadn’t been withheld, and when I looked it up it was for a private investigator.”

She said the situation has left her exasperated and suffering from depression.

“This is an infringement into my family life,” she said.

“The whole situation has made me very ill. It is not right public money is being used in this way.

“I’ve spent £300 on installing blinds on my windows. It was horrible to think someone was watching us.”

Mrs Orchard was exonerated by the probe. She has now left her job with an £11,000 pay-off after signing a “compromise agreement”, agreeing not to take the service to court for human rights violations over “unnecessary surveillance or invasion into privacy and family life”.

In a separate letter, Mrs Orchard was told this clause was added to the service’s usual wording due to the “specific circumstances” of her case.

David Williams, West Yorkshire secretary at the Fire Brigades Union, criticised the need for the fire service to “spy” on its own workers.

“It’s a shame they feel they have to stoop to this level,” he said. “It’s not great when they are spying on their own employees.”

Shipley MP Philip Davies, whose constituency includes Denholme Gate, warned surveillance should only be used where necessary.

He said: “If it is done well then it can work, but it shouldn’t be used whenever someone is off sick.”

West Yorkshire Fire & Rescue Service declined to comment about the matter.

Mrs Orchard has also contacted Carrie Austin, of private investigation firm Local PI, who confirmed to her that one of its agents fitted the GPS tracker to her car, and even asked her for its return.

When contacted, Carrie Austin said she was unable to discuss individual cases due to confidentiality issues.