The Labour Force Survey (LFS), the main Government tool for measuring changes in the workforce, fails to include any foreigners in the country for less than a year. In addition migrant workers living in communal properties are also excluded, meaning many thousands more could also be under the radar.
The omissions mask the total impact immigration has on the British labour force, prompting accusations from the Conservatives than ministers have misrepresented the situation.
In total, foreign workers make up one in seven of the labour market, despite Gordon Brown’s pledge to create “British jobs for British workers”.
Figures in November showed migrants have accounted for all the growth in employment over the past two years while the number of Britons in work has fallen.
Tory MP James Clappison, who uncovered the hidden workers, said: “This underlines the scale of penetration by foreign workers of the UK labour market and undermines still further the Government’s claims about generating new jobs for UK workers.
“This reflects the historically very high number of work permits handed out by the Labour Government to non-EU workers, which is clearly still continuing.
“Labour has systematically misrepresented the level of migration into the country and the effect of its failed efforts to bring it under control.”
The LFS is one of the official employment counts published by the Office for National Statistics (ONS) and is based on a survey of tens of thousands of households.
But statisticians in the House of Commons Library admitted it does not include temporary migrant workers in the count.
That is migrants who are working in the UK for less than a year but, in contrast, the survey does count temporary British workers who may only be in jobs for a few months.
In a letter to Mr Clappison, the official wrote: “Based on ONS experimental short term migration estimates it is estimated that the number of temporary foreign workers not covered by the LFS is approximately 170,000.
“In Jan-Mar 2008 the LFS estimated that there were 3,682,000 overseas-born individuals in employment in the UK (12.5 per cent of all in employment). If we add an extra 170,000 to the foreign worker total from the LFS, the proportion of all in employment who are foreign workers increases to 13 per cent.”
Shadow Home Secretary Dominic Grieve said: “Not only does this reinforce just how unwise Gordon Brown’s boast that he would deliver British jobs for British workers actually was, it also casts serious doubts on the integrity of the Government’s figures.
“Immigration can be of real benefit to the country but only if it’s properly controlled.”
The official said the LFS also ignores anyone, foreign or British, who lives in communal establishments, such as hostels, mobile homes, boarding houses, hospitals and care homes.
It is estimated there are at least 80,000 workers in such establishments at any one time but there is no estimate on the proportion who are foreign.
But given the nature of the some of the accommodation classed as communal, it is likely they are heavily used by temporary migrant workers.
The missing numbers could mean the foreign worker share of the increase in UK jobs between 1997 and 2008 could be as high as 57.4 per cent as opposed to 55.2 per cent as previously thought, the letter said.
However, that is based on the “extremely crude” premise that there were no temporary migrant workers in 1997.
The Daily Telegraph told in November how the overall level of employment increased by about 320,000 between September 2006 and September 2008–up from 29.17 million to 29.49 million.
But during the two-year period the number of British workers in jobs fell by 149,000 while the number of migrant employees increased by 469,000.