Media playback is unsupported on your device Media caption Ed Miliband: "Above and beyond the minimum wage we need to do more"

Ed Miliband has unveiled plans to deliver a "living wage" of at least £7.45 per hour for millions of people, if Labour wins the next election.

Whitehall contracts would only go to firms paying the living wage, while those who paid less could be "named and shamed", said the Labour leader.

His speech came at the start of a week of events promoting the idea.

Downing Street backed firms paying a living wage, but said restricting contracts in this way could be illegal.

Others backing the wage include the Scottish government, which says all staff will get the living wage, and London's mayor, who said it made economic sense.

The living wage - which is £7.45 per hour across the UK except for London where it is £8.55 per hour - does not have any legal force, but is part of a campaign by the Living Wage Foundation and Citizens UK.

It is considerably higher than the official minimum wage that employers must legally pay, which stands at £6.19 per hour for those over 21, £4.98 for those over 18, and £3.68 for 16 and 17-year-olds.

As part of its policy review Labour is looking at ways of making the living wage the new norm, including naming and shaming companies who do not pay the wage and introducing rules forcing government contracts to only be given to those firms who pay it.

Number 10 said the government backed a living wage and "would encourage business to take it up" but warned Labour's plans to restrict government contracts in this way could breach EU procurement law.

Mr Miliband said this was "completely ridiculous" because local councils were already showing it could be done.

What is the living wage and how is it calculated? The living wage is calculated to reflect the basic cost of living and is based on the principle that work should pay enough to provide for the essentials of life.

It is part of a campaign led by the Living Wage Foundation and Citizens UK.

It is an entirely voluntary scheme for employers and the wage is updated every year.

The Centre for Research in Social Policy at Loughborough University calculates the rate for workers outside London. The Greater London Authority calculates the rate for those in the capital.

The latest annual calculation saw the wage rise by 25p from £7.20 to £7.45 for those outside London and from £8.30 to £8.55 for those in London.

Living wage employers are expected to implement the new rate as soon as possible, and within 6 months of the announced rise. Q&A: The living wage

During his speech, Mr Miliband said: "Just as in the 1990s, the minimum wage was a signature achievement of the last Labour government.

"So in the coming years, the living wage will be central to our work.

"We need to build an economy where everyone has a stake.

"Not where millions of people feel they never have a chance for a decent life however hard they work."

Employers who have voluntarily committed to pay the living wage are expected to start paying the new higher rate within six months of the announced rise.

The Scottish government, which has been paying directly employed staff the living wage since last year, has announced it will implement the rise from April 2013. This will benefit up to 3,300 workers, it said.

Speaking at the launch of the increased London rate, Mayor of London Boris Johnson said paying the wage made "economic sense" for the city by giving employees more spending power.

'Sharing fairly'

He said: "By building motivated, dedicated workforces, the living wage helps businesses to boost the bottom line and ensures that hard-working people who contribute to London's success can enjoy a decent standard of living."

Image caption Marlene Brownlee, a cleaner with Newcastle City Council, thinks she will be £70 a week better off

If everyone was paid the living wage, the Institute for Fiscal Studies estimates, the Treasury would save £1,000 a year for every person from less spending on tax credits and from increased tax revenue.

Barclays is one of a number of major companies already paying the living wage while 19 local authorities have been accredited as "living wage employers", including Newcastle City Council.

One of those benefiting is cleaner Marlene Brownlee, who has worked at Newcastle's civic centre for 15 years and estimates she will be about £70 a week better off.

She said: "It'll make a big difference... that little bit extra - well I'm saying little, it's a lot really - is excellent, for me and everybody else at the council."

Mr Miliband unveiled the new policy at Islington Council in London, which recently became another "living wage employer".

He said: "There are almost five million people in Britain who aren't earning the living wage; people who got up early this morning, spent hours getting to work - who are putting in all the effort they can - but who often don't get paid enough to look after their families, to heat their homes, feed their kids, care for elderly relatives and plan for the future.

"Too many people in Britain are doing the right thing and doing their bit, helping to build the prosperity on which our country depends, but aren't sharing fairly in the rewards."