Analysis by the organisation reveals 1.1 million employees get no paid holiday at all and women are worse affected than men.

The sectors with the highest numbers of staff losing out on their legal holiday paid entitlement are education, retail, and health and social care.

The TUC said the main reasons people are missing out are: workers being set unrealistic workloads that do not allow time to take leave; employers deliberately denying holiday requests; and bosses not keeping up to date with the law.

People who work excessive hours are at risk of developing heart disease, stress, mental illness, strokes, and diabetes, the union said.

It is calling for HMRC to be granted new powers to clamp down on employers who deny staff their statutory holiday entitlement.

TUC General Secretary Frances O’Grady, said: “Every worker deserves a break to spend time off with friends and family. But millions are missing out on the paid leave they are owed.

“British workers put in billions of pounds worth of unpaid overtime as it is. Employers have no excuse for robbing staff of their leave.

“The government must toughen up enforcement to stop bosses cheating working people out of their holidays. And ministers must not resurrect tribunal fees which stopped people enforcing their rights.”

What are your rights?

UK workers are entitled to a minimum of 5.6 weeks of paid leave. This means 28 days for a typical five-day week, with pro-rata entitlement for those who work fewer than five days.

The minimum entitlement includes the UK’s public holidays.

Workers might be entitled to additional leave in their employment contracts.