UK 'e-borders' programme unable to help track immigration

UK border control at Heathrow airport in London. Photograph: Gregory Wrona/Alamy

The Home Office's £500m "e-borders" programme which is designed to check everybody in and out of Britain and has taken more than 10 years to develop cannot be used to estimate immigration, ministers have admitted.

They told MPs on the public administration select committee (PAC) that data from the flagship programme cannot be used to replace the existing methods of estimating net migration to Britain because it doesn't collect information about whether passengers are long-term migrants or just visitors or tourists.

In fact the Home Office has said it would be illegal under European Union legislation on free movement to routinely ask passengers how long they intend to stay or their purpose in entering the UK.

The disclosure that the programme, which has cost at least £500m, cannot be used to provide a proper count of migration came in an official response to a PAC report which had said the existing method of estimating net migration based on the international passenger survey (IPS) was "not fit for purpose".

The MPs recommended that ministers should no longer base their key immigration target of getting net migration below 100,000 by next year's election on "such an uncertain statistic".

Home Office ministers rejected the MPs' claim that the IPS, in which more than 700,000 passengers are interviewed a year, was inadequate for measuring, managing and understanding migration levels.

In their official response published on Tuesday, ministers said they didn't agree and cited the UK Statistics Authority in supporting their view that the IPS remained as reliable and accurate as possible and was "currently the best available estimate of 'net migration'".

The official reassurance follows the disclosure earlier this month by the Office of National Statistics that net migration – the number of people coming to live in the UK for more than 12 months minus those going to live abroad for more than 12 months – had been underestimated by 346,000 between 2001 to 2011. The ONS said improvements to the IPS since 2009 had dealt with the problem.

MPs on the PAC had told the Home Office they were so unimpressed by the estimates based on the survey that the ONS and the Home Office should move as quickly as possible to start using e-borders data to measure immigration, emigration and net migration.

But the Home Office said the border system programme, as it is now called, under which passengers have to supply their name, nationality, gender, date of birth and passport details, could not be used to replicate the questions asked during the in-depth survey.

"Partial questioning would not provide a reliable indication as to whether a person is a long-term migrant and would also be subject to challenge as disproportionate," the Home Office said. "It should be noted that EU free movement legislation supported by historical European court judgements prevent Border Force officers from routinely asking additional questions (eg: on duration or purpose of intended stay) of European Economic Association nationals beyond those necessary to establish nationality and identity."

Ministers said that while the border system data couldn't be used to directly estimate net migration it would help improve the figures as an additional source of information.