Why is workers’ rights not an issue that national governments should control?
Are you saying you wouldn’t trust Labour or the LibDems or SNP to protect workers?
The EU typically has lower standards than the UK and was much later to enact legislation;
Workers in the UK are entitled to five weeks and three days of paid holiday a year (including public holidays). The EU Working Time Regulations of 1998 guarantee four weeks of paid leave. For 35 years before joining the EU, the UK had legislation on paid holidays.
The UK passed the Equal Pay Act in 1970, before joining the EU. Equal pay for men and women is nothing to do with Brussels either.
The 52 weeks of statutory maternity leave in the UK is considerably longer than the 14 weeks guaranteed by EU law.
The EU’s Working Time Directive governs the hours employees in the EU can be asked to work. The Open Europe think-tank has listed it as the third most costly EU regulation.
Other EU employment law changes have led to a massive increase in the use of zero hours contracts to circumvent things like pension and holiday pay regulations.