Entries and exits

Migration to and from the UK: current

Migrants are people who change their country of ‘usual residence’.

For the purposes of measuring the numbers of people entering and leaving the UK, migrants are defined as those who change their country of usual residence for a period of at least a year. In other words, if someone has been in the UK for at least a year, it has effectively become their country of usual residence.

The measure for this is called ‘long-term international migration’ and it’s the responsibility of the Office for National Statistics (ONS). It is based on the International Passenger Survey (which questions people entering and leaving the country at certain big airports and sea ports), but it also uses Home Office data on asylum seekers and migration figures specific to Northern Ireland.

Only a relatively small number of people surveyed are migrants, so this leaves a big margin of error, and estimates for net migration overall are only considered accurate within (plus or minus) 34,000 people.

The ONS publishes long-term migration statistics every three months which estimate the number of people entering (immigration) and leaving (emigration) the UK. This data is broken down by nationality and people’s reason for moving. The headline ‘net migration’ figure amounts to immigration minus emigration.

There are more detailed figures released every November. This data provides information on migrants’ country of previous residence, country of birth, main reasons for moving, occupation prior to moving, age, sex, marital status, destination within the UK, and intended (and actual) lengths of stay.

Migration to and from the UK: historical

The Office for National Statistics (ONS) has collected long-term international migration figures back to 1991. This historical data is accessible from the annual release.

However, the International Passenger Survey (which is the main source of the ONS measure) has been around since 1964 and these figures are also included in the annual release.

It’s not as useful as the ONS measure because it doesn’t include asylum seekers monitored by the Home Office or Northern Ireland border crossings. In addition, it only records how long passengers ‘intend’ to stay rather than how long they actually stay (which the ONS account for with the help of exit surveys).

Meanwhile, the House of Commons Library has collected migration figures dating back to 1901. However, this data is less accurate because it’s based on Census figures which assume that population change that isn’t accounted for by births and deaths is due to migration.

Immigration from Eastern Europe

In May 2004, 10 countries joined the EU. Cyprus and Malta were already members of the Commonwealth and so, compared to the other eight countries, their residents already had fewer restrictions on their right to enter the UK.

Immigration from these remaining ‘A8’ countries – the Czech Republic, Estonia, Hungary, Latvia, Lithuania, Poland, Slovakia and Slovenia – has had an effect on the UK population.

The Office for National Statistics (ONS) published a one-off summary of the effects of ‘A8 migration’ on the UK. This includes data on the total number of migrants from these countries and how many of them are students or workers. There’s also information on the age and sex of migrants.

How much of population growth is caused by migration

The UK population is almost always growing, but there are two main causes of population increase: natural change (more births than deaths) and migration.

The Migration Observatory at Oxford University has produced a study analysing how migration has affected UK population growth since 1991.

Visas

The Home Office publish immigration statistics which provide information on visa applications by type (including those for work, study and asylum). This data is published every three months.

Visitors

The main migration figures measure ‘long-term’ migration. They disregard people visiting relatives for short periods or those who come to the UK on temporary work contracts.

However, short-term immigrants (those here for less than a year) are still counted by the International Passenger Survey when they depart the UK. Every year the Office for National Statistics (ONS) produces estimates of the number of short-term immigrants. The data is broken down by age, sex, nationality, country of origin, and reason for moving.

International comparisons

The EU’s statistics agency, Eurostat, publishes international comparisons of migration. This allows the UK’s migration levels to be compared by immigration, emigration and net migration. Over the last decade the data has also been broken down by nationality and country of birth.

The Organisation for Economic Co-Operation and Development (OECD) has a similar database that includes countries outside the EU.