What does this show?
This chart illustrates how the "disposable" income of the UK's poorest and richest households has changed between 1980 and 2013.
The Office for National Statistics, which published the figures, defines this as annual net income after direct taxes such as income tax, national insurance and council tax. The ONS adjusts these figures to account for inflation and the number of people in a household.
While median household disposable incomes increased by 81 per cent over this period to £23,316 in 2012-13, this was almost unchanged from 2002-03.
Has the gap between rich and poor grown?
By this measure, income inequality is greater today than in 1980. Households in the top quintile of incomes have enjoyed the largest average rise in post-tax incomes - 119 per cent - over this period. This is significantly higher than the average increase of the lowest earners, who saw an increase of only 74 per cent.
Although average post-tax incomes of top earners stood 5.3 times greater than low earners' in the 2012-13 tax year, compared to only 4.2 times in 1980, inequality has been greater for much of this period.
So income inequality has fallen recently then?
The disposable income gap peaked in 1990, when top-earning households enjoyed average post-tax incomes 6.4 times greater than the bottom quintile.
This followed a steep increase of 63 per cent in the disposable incomes of high earning households between 1984 and 1990, when income tax rates were cut significantly. During this six-year period, the disposable incomes of low earners rose by only 3 per cent.
More recently, while median disposable incomes - and those of the highest earners - fell in real terms by 5 per cent from their 2007-08 peak to 2012-13, those of the lowest quartile of households increased slightly, by 3 per cent.
Why have poorer households bucked this trend?
A big factor is wage growth. Recent figures from the Institute for Fiscal Studies showed that the post-crisis squeeze on salaries has been tighter towards the top of the pay scale.
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FOLLOW USΑκολουθήστε τη σελίδα του Euro2day.gr στο LinkedinAlthough the think-tank said the findings were surprising, one explanation put forward was that the minimum wage - which increased from £5.73 to £6.31 per hour between 2008 and 2013 - rose faster than median pay.
What about the impact of tax reforms?
While millions of low earners were adversely affected by the axing of the 10p rate of income tax in 2007, moving them to a marginal rate of 20p, this has been largely offset by increases to the tax-free personal allowance.
High earners meanwhile have been disproportionately affected by a number of tax increases, which have contributed to lower disposable household incomes. In 2010, a 28 per cent rate of capital gains tax rate was introduced for higher rate taxpayers, up from 18 per cent which basic rate taxpayers continue to pay.
Taxpayers with annual salaries above £150,000 were also stung with the introduction in 2010 of a 50p marginal income tax rate, lowered to 45 per cent in April 2013.
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