Ed Miliband has called for the establishment of an official Living Standards Index (LSI), with equal status to measures such as GDP, so governments can be held to account on their record on ordinary families’ finances as well as their performance on economic growth.

The Labour leader has written to the chairman of the UK Statistics Authority, Sir Andrew Dilnot, asking him to consider introducing a new quarterly index, which would aim to track ordinary people’s experience of the economy, including the impact of wages, prices, taxes and benefits on their incomes.

The new indicator would be drawn up by the independent Office for National Statistics, and the Office for Budget Responsibility would be expected to issue LSI forecasts in the same way as it does for GDP.

A Labour government would make the LSI level “the key measure” for assessing its performance, said Mr Miliband.

Labour strategists have put living standards at the heart of the party’s campaign for the May 7 general election, when the party calculates that voters will go to the ballot box worse off than at the start of the Parliament for the first time since the 1920s.

Mr Miliband said that current measures of wages, income and prices do not reflect the experiences of British families, whose wages Labour argues have fallen sharply in real terms since the creation of the coalition Government in 2010.

“The current Government’s failure on living standards means working people have seen their wages fall by more than £1,600 a year since 2010 while full-time workers have seen their pay fall by over £2,000 a year,” he said.

“Indeed, this is set to be the first time since the 1920s that people are worse off at the end of the Parliament than they were at the beginning.

“This does not only cause hardship and pain for millions of families, it has also directly contributed to the Government’s failure to clear the deficit with stagnant wages leading directly to reduced tax revenues and higher welfare bills. Income tax receipts have fallen short of their 2010 expectations by more than £68 billion and revenue from National Insurance Contributions by £27.3 billion.”

Mr Miliband added: “T he experience of everyday families too often does not make its way into the minds of policy-makers because current measures are flawed: the wage index ignores the growing number of self-employed; income data is a year out of date; and there is disagreement on which – out of a myriad of different indicators on prices – to use.

“And too often people look at the growth figures or hear the boasts from George Osborne and know these don’t reflect what is happening in their life.

“People are working harder and harder but getting nowhere; the feeling of dread that comes when bills come through the letterbox; the worry that money will not stretch to the end of the month.

“We measure so many aspects of our economy but the one thing we don’t properly measure is the thing that matters most: the success of working people.

“It’s time we had a measure of the success of our economy which reflects the success of working people.

“That is I how judge the success of our country and how I will judge the success of my government.”

In his letter to Sir Andrew, Mr Miliband said an LSI measure should be produced at least quarterly and based on data no older than six months; should reflect people’s real experience of the economy; and should show the experience of people across the full range of income distribution, and pick up how changes in wages or prices vary for those at the top, middle and bottom.