BOSSES are spying on staff using a Big Brother-style tracker to monitor their every move.

The high-tech device records sleep patterns, fitness, productivity and can even analyse emotions.

4 Bosses are spying on staff with Big Brother style trackers, which monitor their every move - recording sleep, fitness, productivity and emotions

It is already being trialled by four British outfits — including accounting giant Deloitte, parts of the NHS, a high street bank and a retailer.

Supporters claim the credit-card sized tracker, which is worn round the neck, will increase productivity.

But campaigners last night blasted the move and insisted it was yet another invasion of privacy.

4 The trackers are worn around the worker's necks, and allow bosses to check up on them

Renate Samson, chief executive of Big Brother Watch, said the device risked turning humans into robots.

She said: “It is unacceptable for businesses to discriminate against staff based on the monitoring and tracking of their personality, fitness and out-of-work lifestyle.”

The tracker is worn for 24-hours and the results are combined with data gathered from emails and phone calls to establish how much work is being done.

4 Renate Samson, head of Big Brother Watch claimed the device is unacceptable and will turn humans in to robots Credit: BBC

The device has a built-in microphone for voice analysis to assess stress and coping levels and a Bluetooth sensor to monitor body language around colleagues.

GPS sensors track employees around the workplace, monitoring how much they talk to colleagues and overall physical output.

It can even detect if an employee is drunk.

Ben Waber, chief executive of Humanyze, which makes the badges, said they would revolutionize working practices.

4 Finance giant Deloitte, some parts of the NHS, a leading high street bank and a retailer are all thought to already be using the devices Credit: Alamy

He said: “It’s looking at the amount of time you talk, who you talk to, your tone of voice, activity levels, dynamics like how often you interrupt.

“By mining that data, you can actually get very detailed information on how people are communicating, how physiologically aroused people are, and can make predictions about how productive and happy they are at work.”

He said the tone of conversations was logged - not the content - and bosses would only get an overview of activity.

related stories PARADISE AISLE Aldi set to become the highest-paying UK supermarket as staff's salary increase trumps the Living Wage RISE OF THE ROBOTS Bosses of Brit firm Capita reveal plans to replace 2,000 employees with ROBOTS WORLD'S BEST BOSS? Company chief splashes out £400,000 to take 100 employees on an all expenses paid end-of-year trip to the Maldives Toxic uniforms? American Airlines employees call for new uniforms to be recalled after complaining of severe reactions 'WE HOPE YOU FAIL!' These hilarious farewell cakes tell leaving employees how it is AIRPORT HORROR Southwest Airlines employee dies after being shot at Oklahoma Airport

Individuals must consent to wearing the badges and 90 per cent did, he added.

The firms believed to be using the badge include consultants Deloitte and parts of the NHS.

A leading UK retailer is also using the badges.