John Hutton says inaccurate population figures caused the error

The Department for Work and Pensions (DWP) has revised its statistics on poverty, first published in March.

It now estimates there were 7.2 million such adults in relative poverty that year, and 5 million working age adults in absolute poverty.

Other estimates for the number of poor children and pensioners are unchanged.

The publication last month of the first estimates gained widespread publicity because they revealed that the number of children living in relative poverty in 2005/06 rose by 200,000 to 3.8 million.

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

John Hutton, secretary of state for work and pensions, 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 said.

"Looking at the measures of relative poverty, correcting the error has had no impact on reported child poverty for 2005/06.

"However, the revised figures do see an increase in reported poverty among working age adults," he added.

Mistake

Relative poverty is calculated as the proportion and number of people living on less than 60% of the current median income.

Absolute poverty describes those who are living below 60% of the median income from 1998-99.

Jonathan Shaw of the Institute for Fiscal Studies said the mistake was unfortunate but did not alter the overall picture.

"What went wrong was a relatively easy mistake to have made," he said.

"But it does not make much difference to the proportion of the population involved," he added.