A top employment lawyer has set alarms bells ringing this week for working people.
Brexit, he says, could end up with the loss of paid holidays, redundancy consultation rights, protection against pregnancy discrimination by employers, and much more.
The independent legal opinion from Michael Ford QC was commissioned by the TUC to help every working person in the UK understand what's at stake for them in the referendum. And the answer is that they have a great deal to lose.
Despite this, recent polling showed that both the Leave and Remain campaigns are failing to connect with blue collar workers' concerns. But when you consider how little attention the campaigns are giving to EU-derived workers' rights, the poll's findings should be no surprise.
Both campaigns need to sit up and take notice of what Michael Ford QC has to say. His independent, expert view is that Brexit could mean a massive step backwards on hard-won rights at work.
His legal opinion says: "It is easy to contemplate a complete reversal of the gradual increase in social regulation protecting workers which has taken place since the 1960s".
And there is plenty of evidence to back up his warning. Even now, six pro-Brexit Conservative MPs are sponsoring a parliamentary bill to allow employers to opt out of the Working Time Directive - the EU agreement that guarantees you a minimum of 20 days paid leave a year. Thankfully our current EU protections will stop this attempt in its tracks. But if we left the EU, it could be open season on rights like these.
You only have to scratch the surface of conservative think tanks reports, or speeches by Ukip supporters and funders, to know what their agenda is. Brexit is a means to an end - and the end they seek is the demise of regulations that are crucial to your rights at work. They casually label it 'red tape', but for you it could be your right to time off if your child has a medical emergency.
We're not saying that all the workplace rights that unions have spent so many years campaigning for at European level will be lost immediately. But one of the things we wanted to know from Michael Ford QC was his expert view of which rights are most at risk.
His answer isn't comforting.
On the list of rights most at risk are guarantees of fair treatment for agency workers and part-timers. Remember that if they lose their rights, there will be an incentive for bad bosses to push more workers onto casual contracts to drive down everyone's terms and conditions.
Women at work are at risk of a gradual erosion of their rights to fair compensation if they are discriminated against, for example over pregnancy and maternity provisions.
It would also be possible to whittle away at people's rights to proper holiday pay, rights when you're off sick, and payment for time spent on-call or travelling from job to job.
And that could be just the start. Michael Ford QC writes in his opinion that "there is no precedent for the kind of radical overhaul of laws which would potentially flow from Brexit".
Given that the government's direction of travel is already to cut workers' rights, the threat feels very real. The current government, and its coalition predecessor, restricted protections against unfair dismissal, reduced TUPE rights for workers whose jobs are outsourced, and raised Employment Tribunal fees to levels that deter people from enforcing their rights.
So can you really trust the government to restore all your EU rights under UK law without relishing the opportunity to dilute some, and scrap others?
Voting to leave the EU would be a big risk for every working person. It would leave them haunted by years of uncertainty, with rights like paid holiday, parental leave and equal treatment for part-timers at risk of being whittled away.
Generations of trade unionists fought hard to win the rights that the EU now guarantees. If we lose them because of Brexit, it could take generations to get them back again.
The biggest cheerleaders for Brexit think that your protections at work are just red tape to be binned. Bad bosses will be rubbing their hands with glee if leaving the European Union gives them the chance to cut back workers' hard-won protections.
We shouldn't give them that opportunity.
Frances O'Grady is the general secretary of the Trades Union Congress (TUC)