The chancellor is set to increase the amount employers in the UK pay in National Insurance at the Budget.

Rachel Reeves is also expected to lower the threshold for when employers start paying the tax, but is not likely to introduce the levy to employer pensions contributions.

It is understood the changes could raise £20bn for public services, such as the NHS.

The move is thought to be the single largest revenue raiser of next week's Budget, but other tax rises are also expected.