The Prime Minister will say: “I said I would use Brexit to extend the protections and rights that workers enjoy, and our manifesto will deliver exactly that. Our plans, backed up with strong and stable leadership, will be the greatest expansion in workers’ rights by any Conservative Government in history.

“By working with business, reducing taxes and dealing with the deficit we have delivered steady improvements to the economic prospects of working people. Now is the time to lock in that economic growth and ensure the proceeds are spread to everyone in our country.

“There is only one leader at this election who will put rights and opportunities for ordinary working families first. The choice next month is clear: economic stability and a better deal for workers under my Conservative team, or chaos under Jeremy Corbyn, whose nonsensical policies would trash the economy and destroy jobs."

The new entitlement to care leave is likely to be modelled on a similar policy in Ireland, where workers can take between three months and two years off to help loved ones.