The charity also found that two in five people on temporary contracts wrongly believed they’re not entitled to paid holiday.

It said that some employers are misleading employees about holiday entitlement due to “bosses’ ignorance” while others were deliberately flouting the law, exploiting workers’ confusion.

In the last financial year, 185,000 people received help from Citizens Advice relating to employment issues and 10,000 of those were specifically about paid holiday. Over the same period the Citizens Advice webpage on paid holiday had 260,000 visitors.

In one case, the charity helped a man who worked in a care home for over five years and who worked 48 hours a week. His employer had previously told him that night workers were not entitled to paid holiday, and he hadn’t questioned this policy. After speaking with Citizens Advice, the charity calculated he had missed out on paid holiday worth £8,900.

Another woman who worked in the sales sector was told she could only take holiday if she met her sales targets, which is unlawful.

Separate research found that between a third and half of employers use fixed term or temporary workers and more than half (57%) of employers use variable hours or shift work.

Citizens Advice is calling on the next government to improve issues for zero hours contract workers.

‘Dirty tactics’

Citizens Advice chief executive, Gillian Guy, said: “Thousands are missing out on rights they are entitled to due to a lack of awareness, confusion and in some cases deliberate dirty tactics by employers.

“With more than half of employers having staff working shifts or variable hours, action needs to be taken now to protect workers rights.

“There’s been welcome attention from political parties on issues surrounding rights at work, and we hope that the next government takes steps to make people’s jobs and income more secure.

“Citizens Advice is calling for all employment rights enforcement to be brought into one Fair Work Authority that can tackle employers that break the rules. We also want to see a £50 cap on Employment Tribunal fees, so that people who are treated unfairly by their employer aren’t priced out of justice.”