UK population increase through migration

29 August, 2005

1. Figures released by the Office of National Statistics (ONS) on 25th August 2005 show that the population of the United Kingdom reached 59,835,000 and England's population passed 50 million for the first time in mid-2004. The UK's population increased by 281,200 over the year to 30.6.2004. It is likely that, if this trend has continued over the last year, the population of the United Kingdom now exceeds 60 million people.

2. Since 1997 most of the annual increase in population has resulted from immigration to the United Kingdom as the following chart shows:

3. As can be seen from this chart net migration rose steeply from 1998 to 1999, reaching a peak of 194,000 in 2000-2001. After dipping slightly for 2 years to around 150,000 it has increased again to 187,000
[1] . In the 7 years from mid 1997 to mid-2004 it has directly added over a million people (1,075,000) to the UK's population out of a total increase of 1,521,000. That is nearly three-quarters (71%) of the population rise is directly due to migration.

4. Even this understates the true contribution of migration to population increase. Migration has a major impact on the other component of population increase namely natural change - the excess of births over deaths.

5. The impact of migration on the natural change component of population increase in the period 1997-2004 consists of:

a. Births to foreign-born mothers who have migrated to the UK
b. Less Births to British-born mothers who have emigrated
from the UK
c. Less Deaths of immigrants
d. Plus Deaths of emigrants

6. Data obtained by Migration Watch from the government's Labour Force Survey shows that by Autumn 2004 foreign-born mothers who migrated to the UK between 1997 and 2003 inclusive had given birth to 174,000 children since arriving in the UK
[2] .

7. In contrast there are likely to have been very few births to British born females who have emigrated from the UK. The reason for this is that the levels of net emigration of British born females in the 15-44 age group is very small

8. Similarly factors c and d will have had very little overall impact on the population because immigrants to the UK are typically young - for instance in the period 1997-2003 there was a net inflow of 508,000
[4] males aged 15 to 44 out of a total net inflow of 526,000 males. In the older age group of 45 to 64 there was, in contrast, a net outflow of men in this period of 28,000. The higher mortality rate of the older men leaving the country therefore goes some way to balancing the lower mortality rate of the very much higher number of younger men entering the country. [5]

9. We estimate that the overall effect of factors 5b.,c. and d. will be very small - in the order of 10,000 net reduction to the population contribution of migrants.

10. Our estimate of the total contribution of net migration to the UK's population in the 7 years from mid 1997 to mid 2004, when births to, and deaths of, the migrant population are taken into account, is therefore about 1,239,000 people out of the total rise in population of 1,521,000 or 81%.

11. 1,239,000 people is equivalent to adding cities of the size of Birmingham (977,000) and Nottingham (267,000)
[6] to the UK in just 7 years. It equates to an average growth in population attributable to migration of 177,000 each year.

12. This total does not include some categories of illegal immigrants - namely those who have entered the country without detection or through false documentation and those who have entered on a short term permission (less than 1 year) and have overstayed. The Government recently estimated that there were 430,000 illegal migrants in the UK. We know that about 40,000 clandestine entrants are detected every year. It therefore seems reasonable to assume that illegal immigrants in the categories listed above amount to at least 30,000 a year. If these are included, immigration will be adding about 200,000 a year to the UK's population or, at this rate, two million every ten years. This has very serious consequences for the environment, our infrastructure (especially housing, transport and schools) and for social cohesion.


[1] The ONS data at says that the change in population due to migration and other changes is just under two-thirds of the total change. 187,000 has been calculated as two-thirds of the total. (Other changes are primarily movements of non-civilian. These changes have been small in recent years. In previous years 'other changes' have included an adjustment to reconcile the mid-year population estimates with the 2001 census)
[2] From Labour Force Survey - Autumn 2004. Analysis carried out for Migration Watch of children born in the UK of foreign born mothers by mother's year
of arrival.
[3] Source ONS: International migration MN series. Total net emigration of British born people taken from table 2.5. There is no detailed data directly supporting this to show the numbers who were female and their age breakdown. However, the annual data for 2000-3 taken from the International Passenger Survey, indicates that about 36% of British-born emigrants were female. Data for net emigration of British citizens (as a proxy for British born) show that under a quarter were aged 15-44 - implying that <10% of net British born emigrants are females aged 15 to 44. Assuming that the age of the emigrants is evenly spread across the age range and they have a total fertility rate of 1.7 a very rough estimate would suggest that about 8,000 children would have been born to these emigrants.
[4] ONS MN30 - International Migration - net migration by age and sex -
table 2.9
[5] There are estimated deaths of just over 2,000 of the net migrant population. This has been calculated by taking the net migrant population by age and sex for each year from 1997 to 2003 and 'ageing' it (using current life tables from the Government Actuary's Dept) to calculate the population in 2004. The difference is the estimated number of deaths (just over 2,000).
[6] Source: 2001 census