Asda workers in Scotland are set to protest over a controversial new contract.

Protesters from throughout the UK have already submitted a 23,000-strong petition to the company earlier this month as part of a campaign by the GMB union.

On Tuesday afternoon, supermarket staff will begin a protest outside GMB's Glasgow office before taking their demonstration to the Scottish Parliament in Edinburgh ahead of a debate.

According to GMB, up to 12,000 workers face the choice of signing the contract, called contract six, or risk being sacked next month in the run up to Christmas.

The union claims Asda Walmart's new contract - which increases the base rate of pay to £9 per hour - offers reduced terms and conditions, which will see staff lose paid breaks and affect their holiday entitlement.

However, Asda said the change "represents an investment of over £80m and an increase in real pay for over 100,000 of our hourly paid colleagues".

Earlier this month, the union branded Asda "heartless" when company bosses handed out leaflets with tips on getting a new job. It suggested staff use their local job centre and offered advice on CV sharing.

Gary Carter, GMB national officer, said: "Contract six is shocking - the changes are forcing our members to choose between looking after their families, or being able to support them. It's a disgrace."

An Asda spokesperson responded: "Whilst we respect the right of the GMB to express its views, the comments around Asda colleagues being sacked due to commitments outside work are untrue.

"This change represents an investment of over £80m and an increase in real pay for over 100,000 of our hourly paid colleagues.

"Throughout the consultation process on these changes we have taken colleague concerns and feedback from colleague representatives - including the GMB - on board and have been clear that we understand our colleagues have responsibilities outside of work and we will always help them balance these with their work life.

"We have been clear that we don't want any of our colleagues to leave us and whilst the vast majority of colleagues have chosen to sign the new contract, we continue to have conversations with those who have chosen not to, to try and understand their concerns.

"It is vital that we make sure we are prepared to adapt to the demands of our market. Change is never easy, but we are determined that Asda remains a sustainable business for its customers and colleagues - now and in the future."