The truth behind UK migration figures

Heathrow border control

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Ever wondered how many people are moving to, and leaving, the UK? If so, you're not the only one - the official figures are said by some experts to be based on not much more than guesswork.

Yes, despite few issues mattering more to politicians and the public than migration, the UK still does not have an accurate system for counting people in and out.

The e-borders scheme - which was meant to do this job - is still a work in progress, and despite government assurances to the contrary, there are some who fear it might stay that way.

Instead the government relies on the answers given by a sample of travellers who agree to be stopped and questioned by a team of social survey interviewers at Heathrow and other main air, sea and rail points of entry to the UK.

And despite the increasingly high hurdles to jump through to get a visa to come to the UK, it seems there is no way of knowing if someone is still in the country when it expires.

UK population

Crowd of shoppers
  • According to the 2011 census there are 53 million people in England; 3.1 million in Wales; and 1.8 million in Northern Ireland
  • The figure for Scotland - and the whole of the UK - will be announced in December
  • The population of England and Wales has risen by 3.7 million in a decade - the largest increase since records began
  • The growth was fuelled by increased life expectancy, a rise in fertility rates and immigration
  • The 2011 census could be the last - the government is looking into cheaper and more responsive alternatives

Keith Vaz, chairman of the influential home affairs committee says he finds it incredible that a supermarket loyalty scheme can collect and store details on the shopping habits of millions of people, yet a similar database can not be set up to record arrivals and departures.

Particularly when the coalition government sets such store by reducing "net migration" - the difference between the number of people entering and leaving the country.

So if Britain does not count everybody in as they arrive, and count them out again as they depart, where exactly do the net migration figures announced each quarter by the government come from?

The main source is the International Passenger Survey (IPS), which was designed in the early 1960s to find out how much foreign tourists were spending in the UK - something it is still used for today.

It works something like this: There are about 240 IPS officials stationed at major airports and ports around the country.

They pick out every 10th, 20th or 30th passenger streaming through arrivals or departures, depending on how busy they are that day, and ask if they wouldn't mind taking part in a short survey.

"There may be times when, owing to a particular flood of passengers, you just cannot keep an accurate count. Do not panic if this happens but keep counting as best you can," advises the Office for National Statistics training manual.

'Hopelessly inadequate'

The ONS takes the raw IPS data and adds information about asylum seekers and migration statistics from Northern Ireland, as well as figures for people who have entered the country on short-term visas and decided to ask to extend their stay, before arriving at a final immigration figure.

About 300,000 people are interviewed each year by IPS officials - about 0.2% of the 200 million who enter and leave the UK over the same period.

The IPS has been considerably beefed up in the past three years, after it came in for stinging criticism from senior figures, including Bank of England governor Mervyn King, who branded it "hopelessly inadequate".

The ONS admits the survey is still not perfect but points out that 800,000 people are sampled to find the 300,000 interviewees and it has cast its net wider than Heathrow, where most interviewers were based, to other airports around the country and ferry terminals at Dover and Portsmouth it says 95% of travellers now "have a chance" of being interviewed.

It also has the virtue of being long established and relatively cheap.

But it is entirely voluntary and despite the training manual's advice to interviewers to be cheerful at all times - "no one wants to be interviewed by an unsmiling person with a dreary monotonous voice". Although the response rate is 78%, the ONS says that only 2% of people approached refuse to take part in it.

Passengers travelling at night, when interviews are suspended, or on smaller, low volume routes also slip through the net.

The one thing the IPS has over other sources of data on immigration - such as the number of non-EU passengers passing through border control, new NHS registrations or new National Insurance numbers - is that it records how long migrants say they intend to stay in the country.

Graph How accurate are the official net migration figures?

But its major flaw, according to experts, is when it comes to measuring how many people are leaving the country.

IPS emigration estimates are based on interviews with just 2,000 people (who, the ONS point out, are found from interviews with about 400,000 interviews) - and there is currently no alternative source of data to measure them against.

This matters because the coalition government has promised to reduce net migration - the difference between those entering and leaving the country - to "tens of thousands" by 2015.


Home Secretary Theresa May hailed "the first significant falls in net migration since the 1990s" in her keynote speech to the Conservative Party conference.

What she failed to mention was that when that "significant fall", from 252,000 to 216,000, was announced, the margin of error was also revealed for the first time.

What happened to e-borders?

Tony Blair
  • Tony Blair launched the £1.2bn e-borders programme in 2003
  • It was meant to collect details from passenger lists of all people entering and leaving the UK so that they can be checked against security watch lists
  • All flights from outside the EU are now part of e-borders
  • Ports and railway stations are due to follow by 2014
  • EU flights are meant to be covered by 2015
  • But that will depend on reaching voluntary agreements with other nations - and solving commercial problems
  • The US firm handed a £750m contract by Labour to deliver e-borders, Raytheon, was fired by the coalition in 2010 for "extremely disappointing" performance
  • The company is seeking £500m in damages from the government
  • The e-borders contract was split in two with IBM and Serco given the job of getting a system in place at nine airports before the Olympics
  • The contract for the post-Olympics element of the programme - the biggest part of it - has yet to be awarded

This showed that the main source of these figures was only accurate to within plus or minus 35,000 people.

In other words, according to the ONS, the fall was not yet statistically significant.

This does not mean, of course, that net migration has not fallen, just that, according to some experts, the government's main method of measuring its progress is little better than a rough guess.

"It is very difficult to assess how well the government is progressing toward its target of reducing net-migration to the 'tens of thousands', or to evaluate the effects of specific policy changes," says Dr Martin Ruhs, Director of the Migration Observatory at the University of Oxford.

"In simple terms the government could miss the 'tens of thousands' target by many tens of thousands and still appear to have hit it - conversely the government could hit, or even exceed its target and still appear to have missed it."

The government denies that the IPS is a faulty instrument for measuring its progress on migration.

In a statement to the BBC, Immigration Minister Mark Harper said: "The International Passenger Survey already provides the ONS with a reliable method of measuring net migration.

"By 2015, we aim to reintroduce exit checks using the e-borders system, which will allow us to build an even more accurate picture of the number of people entering and leaving the country."

A brainchild of the Tony Blair era, when it seemed as if there was no problem that could not be solved by a multi-billion pound IT project, e-borders was meant to replace the old paper-based embarkation system, which was scrapped in the 1990s.

Since then departures from the UK have not been officially recorded.

So it is possible for migrants to enter on short-term visas and - unless they notify the authorities of their intention to stay longer or are really, really unlucky and are picked up in a Border Force raid - stay in the UK or leave the country years later without showing up in the official records.

It was one of the justifications Mr Blair made - and is still making - for the introduction of an identity card system.

E-borders which was primarily meant to improve security, when combined with a biometric identity card scheme, began collecting details of passenger and crews for inbound flights from outside the EU at nine airports in March.

The plan now is to extend it to ports and railway stations by 2014 and to passengers from within the EU by 2015.

But that will depend on persuading all EU countries to share passenger and crew list information - quite a number of them regard this as illegal under European free movement laws.

High hopes

And there are some, such as Keith Vaz and Sir Andrew Green, of think tank Migration Watch, who fear the project, which was meant to be up and running in time for the Olympics, may have stalled altogether.

"The government will rightly be held to account if they fail to achieve a steady and substantial reduction in net migration, whatever the technical details," said Sir Andrew.

"But it is time we were told more about the purpose and progress of the e-borders programme."

The statisticians at the ONS still have high hopes that e-borders will one day be able to provide reliable migration statistics.

But they say it will be 2018 at the earliest before they can even start incorporating data from the programme into their estimates - and there are no plans to replace the IPS as the main source of migration data.

So until the Home Office can be persuaded to come up with a different method - the men and women of the IPS will continue to put on their best smiles and try not to panic as they scan the arrivals halls of Britain's ports and airports.

And net migration statistics should continue to be taken with a major dose of salt.

Graph showing increase in migration

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  • Comment number 94.

    This comment was removed because the moderators found it broke the house rules. Explain.

  • rate this

    Comment number 93.

    I am totally and absolutely against immigration into GB. We have a huge unemployment problem and an establishment which doesn't care about the native British population. The gang in charge - any of them - should be investing in our own people first. If we don't have enough skilled people, then train them!! if no-one wants low-paid work, pay more!!

  • rate this

    Comment number 92.

    Perhaps they should award the contract to Tesco, as they seem eminently qualified to carry out this kind of record keeping.

  • rate this

    Comment number 91.

    18-Our Commonwealth cousins down under in Oz can teach us a thing or two!

    So what can the Australians,with their immigrant PM from Barry,Wales teach us?

  • rate this

    Comment number 90.

    This lack of knowledge of numbers or managing immigration, especially as many immigrants have much larger families, is unworkable for those that have to cope with essential services such as schools, nhs and housing. If numbers are not known, how can anyone be able to make sure services are available at the right levels?

  • rate this

    Comment number 89.

    When it comes to immigration I no longer believe anyone other than Sir Andrew Green and maybe Frank Field

  • rate this

    Comment number 88.

    This situation strengthens the need for ID cards for all. I have lived in Spain and have a EU citizen ID number which I require to show when I rent a house, buy a car, etc. Legal non-EU citizens should be issued with an ID card in the UK and be required to show it to obtain a drivers licence, rent or buy a house etc.

  • rate this

    Comment number 87.

    I think we should be careful about throwing the word racism about, without a doubt there are some who oppose immigration from a perspective of, all immigration is bad immigration but they are a minority. Most of us would just like to see some honesty, clarity and some sort of proper controls applied..

  • rate this

    Comment number 86.

    Tighter controls are long overdue, using the fact that migrants from EU countries are free to travel between those countries is one thing but a lot of migrants are using EU countries as an entry point to the UK. The fgure permitted should be capped, afterall the UK is an island is is not capable of sustaining long-term influx of migrants.

  • rate this

    Comment number 85.

    How very convenient. So really we have no idea at all how many folk are leaving. All 'net' figures are therefore nonsense.

  • rate this

    Comment number 84.

    67. LabourBrokeBritain
    I'd also like them to make more of an effort to stop criminals coming here
    Some criminals are extremely wealthy and we have some of the world's finest reputation-washing organisations. If you've lived abroad and read the local (free - usually online only) press, you'd be aware of some deeply dodgy characters scurrying away to "do a PhD" in the UK.

  • rate this

    Comment number 83.

    How many people working on our borders are Brits

  • rate this

    Comment number 82.

    Hey Winkless
    Are you telling us that you don't feel oppressed,controlled and demoralised already.

  • rate this

    Comment number 81.

    Racist , NO its called freedom of speech .

  • rate this

    Comment number 80.

    The way the figures are calculated isn't right in my opinion. To give a theoretical example, if 50,000,000 people from India arrived in Britain in 2013 and 50,000,000 people departed these shores then there would he ZERO NET IMMIGRATION yet the whole country would have changed and become a little India. The whole system is potty. We should just look at immigration ignoring emigration.

  • rate this

    Comment number 79.

    I strongly object to the comment that the BBC is being racist by raising this important issue. We still live in a free society and the voice of the people is vital in maintaining this otherwise we become oppressed controlled and demoralised. Well done the BBC!

  • rate this

    Comment number 78.

    #47 who does represent britain then? why are british people living rough on the streets while there are unskilled immigrants from eastern europe here living in council houses.

  • rate this

    Comment number 77.

    I have travelled to many countries, for work, and found that even the third world countries on the west coast of Africa have better controls over immigration and check your visa going BOTH in and out of their countries. Why on earth can’t we do this? It would be good to get a centralised Database of all these comings and goings, but you all know how the government is famous for computer flops.

  • rate this

    Comment number 76.

    67. "I'd be happy if they took race out of the equation and instead stopped anyone who was a member of an oppressive religion coming in."

    No. That would be like placing every Catholic on the sex offender's register. A religion is only as oppressive as the person who uses it to oppress, and that's true of every religion.

  • rate this

    Comment number 75.


    One would have thought that a country that is isolated by water on all sides should be able to monitor all entry numbers and exits.
    We're surrounded by water not isolated by it, if we were immigration wouldn't be a problem by definition.


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