The Government has conceded that there were an extra 100,000 adults living in both relative and absolute poverty in the UK in 2005/06.

The Department for Work and Pensions (DWP) has revised its poverty statistics, originally published in March. It now reckons there were 7.2 million adults in relative poverty that year and 5 million working age adults in absolute poverty.

Estimates for the numbers of poor pensioners and children are unchanged.

The figures are published each year by the DWP in the Households Below Average Income (HBAI) report.

Secretary of state for work and pensions, John Hutton, said: “The mistake that had come to light was due to using inaccurate estimates of the UK population. Most of the key headline figures from the publication are unaffected by this error.”

He continued: “Looking at the measures of relative poverty, correcting the error has had no impact on reported child poverty for 2005/6. However, the revised figures do see an increase in reported poverty among working age adults.”

Jonathan Shaw of the Institute for Fiscal Studies said: “The mistake was unfortunate, but did not alter the overall picture too dramatically. What went wrong was a relatively easy mistake to have made.”