The Office for National Statistics (ONS) produces estimates of net migration. This is the balance between people entering the UK (inward migration) and people leaving.
Where we get the data
These estimates are mainly derived from data obtained from the International Passenger Survey (IPS) – a sample survey of passengers, including British citizens and other European Economic Area (EEA) nationals, arriving at and leaving air, sea and Channel Tunnel ports in the UK.
The International Passenger Survey (IPS) data on migrants provides the basis for the Total International Migration estimates. These data are supplemented with the Irish Central Statistics Office data on flows to and from the Irish Republic. Other data sources allow us to adjust the data to cover migrants that are not captured in these sources. These adjustments and their data sources are:
- Home Office data on asylum seekers and their dependants – these are used to estimate the numbers entering and leaving the UK without being interviewed for the IPS
- IPS visitor data – these are used to estimate the number of people who initially come to or leave the UK for a short period but subsequently stay here or abroad for a year or longer
- IPS migrant data – these are used to estimate the number of people who initially come to or leave the UK for a year or more but subsequently stay here or abroad for less than a year
The data on net migration are subject to sampling and estimation error, and you should not give undue weight to one year’s data.
Find out more about the methodology used on the National Statistics website
Improving Migration and Population Statistics Project (IMPS)
The aims of this project are to:
- improve migration and population statistics produced by the Office for National Statistics (ONS)
- avoid the problems of Census 2001 when there was a large difference (1.2 million) between the Census and the rolled-forward mid-year population estimates (MYEs)
- gain a better understanding of the causes of any difference that does occur
Find out more about the Improving Migration and Population Statistics Project (IMPS)
The difference between inward migration and settlement
The internationally accepted definition used for migration includes migration for a year or longer by, for example, students, workers and asylum seekers. Therefore, inward migration is not the same as being accepted for settlement, i.e. being allowed to stay indefinitely in the UK, especially as settlement can occur several years after entry to the country.
Read more about immigration control.
Our research projects have covered such topics as non-asylum migration flows and the integration of refugees who settle in the UK.
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