The government’s plans for closing the gap between rich and poor will be set out by deputy prime Minister Nick Clegg today.

Mr Clegg is due to deliver a major speech about social mobility at an event hosted by the CentreForum think-tank.

The address - titled Closing the gap: building an opportunity society - comes days after it was announced that Labour former cabinet minister Alan Milburn had been appointed the government’s independent reviewer on social mobility.

Mr Clegg is expected to set out further details about Mr Milburn’s role, which will see the former health secretary report annually on efforts to boost social mobility across government and public bodies, including the NHS and universities.

The Deputy Prime Minister, who is “holding the fort” while David Cameron is on holiday, will be speaking as the coalition marks 100 days in office.

News of Mr Milburn’s role provoked fury from senior Labour figures, including Lord Prescott, who labelled his former cabinet colleague a “collaborator”.

But on Monday Mr Clegg defended the appointment, saying Lord Prescott had “got his ermine in a twist”.

He said of Mr Milburn: “He’s not joining the government. What I’ve asked him to do … is to act as an independent reviewer of how not only the government, but public bodies, universities, the NHS, everybody, is doing to boost what I think is one of the most important things of all, which is social mobility.

“One of the main reasons I came into politics is it really, really gets to me that, even though … we are a relatively affluent country, children are pretty well condemned by the circumstances of their birth.

“Basically, because of where they were born, who their parents were, where they lived, they are going to have less chance of living as long as they want to, of getting the education they want, getting the jobs they want.

“I think a liberal, open, opportunity society has got to be one where we remove barriers to social mobility so you can make of yourself and your life what you want to.”