Amazon treats its workers like "robots with no say", a union has claimed.

The GMB also suggested the online retail giant's workforce are forced to wear electronic devices which monitor their movements.

Leaders have written to councils across the UK to find out if they are in talks with the internet shop after it announced it is to double the number of British facilities.

Amazon, which has warehouses in Gourock, Inverclyde and Dumfermline, Fife, employs around 8000 nationwide, and is planning to expand during the next three years.

But the GMB are calling on councils to let them know any plans to open new warehouses within their boundaries and to ensure that workers are treated fairly.

Martin Smith, GMB National Organizer, said: "Amazon pays its staff just above the national minimum wage of £6.31 per hour.

"Paying a minimum wage rather than a wage workers can live on obliges taxpayers to top up wages for staff with families.

"Working families tax credit is a subsidy to a company like Amazon which pays little corporation taxes.

"Staff complain about a culture of bullying and harassment endemic in the dataveillance that comes from staff being required to wear digital arm mounted terminals AMTs with no agreed protocols r.e. breaks, speeds etc.

"Requiring employees to wear AMTs and subjecting them to dataveillance, while denying them union rights, takes away the consent essential for the positive use of digital arm-band devices. Members say it is human automation - they are kind of robots with no say."

Amazon declined to comment.