Yesterday, Watson joined a protest by trade union GMB outside the London head office of McDonald's over the fast food chain's use of zero-hours contracts.
Speaking to HR magazine, Watson said zero-hours contracts highlight the "continued abuse" of contract law and "undermine workers rights".
"If employers want to be that flexible with wages then they must realise workers can't be. They can't be flexible with shopping bills, rent and mortgage payments," Watson said.
"In tough times an employer can have leverage over their workforce. There's something profoundly unjust in the way people are treated like that."
Questionable claim
This week, VP HR McDonald's Jez Langhorn told HR magazine that a recent staff survey showed 94% of its workforce were happy with the hours and contracts they were on.
He also said the company "never have and never will have" people sitting at home waiting for hours.
GMB national organiser Martin Smith said Langhorn's claim that nearly all employees are happy with their contracts was "questionable".
"What the union is hearing is that people are being sent home from a shift because it's not busy enough. We also know workers are seeing their hours being cut if they make genuine mistakes or take time off sick," he told HR.
"The benefits of a zero-hours contract are a one-way street only favouring the employer."
Smith said he'd like to see someone's average hours over a 12-week period be their contracted hours.
Business secretary Vince Cable is leading a review on zero-hours contracts and is expected to release findings later this month.
