"A mum working full-time, stacking shelves in my constituency, earning just the minimum wage, has nearly £1,000 taken from her in income tax; that's just wrong," said the Hexham MP.

"The Government is right to be raising the tax threshold to £10,000 which will put money into the pockets of everyone working hard for a living, but I would like to see the Government go further."

He added: "I believe that nobody earning the minimum wage and working a standard week should pay tax on that income. "This is a radical proposal, I accept. "It's not Lib Dem policy, nor is it Conservative party policy, but it should be. It's one I'll be championing with ministers."

The scheme would focus on those working hard, putting money on those on the minimum wage as well as those earning £20-25,000 feeling the squeeze, said Mr Opperman. "That's why I support calls for a mansion tax. A bit extra tax on properties over £2m seems perfectly fair to me.

"If you're buying a house worth £4 or £5m then I really think it's fair to ask you to pay a bit more in the country's coffers when you sell it."

But Mr Opperman warned against a rebanding of council tax, saying it would be expensive and hit everyone.

"The mansion tax should be applied as a premium when the house is sold, a bit like stamp duty does now," he said.