Internal Migration

Each year, the Office for National Statistics (ONS) publishes estimates of internal migration (within England and Wales rather than across international borders) broken down by age and sex at country, region and local authority level for England and Wales. As there is no single system to record population movements within England and Wales, internal migration estimates must be derived from proxy sources. The ONS uses three administrative data sources:-

• the National Health Service Central Register (NHSCR),
• the Patient Register Data System (PRDS) and
• the Higher Education Statistics Agency (HESA).

Overall, the accuracy of NHS based data depends on patients re-registering with a new doctor when they change residence or informing their current GP of any change of residential address. It is known that re-registration rates vary by sex and age group.

The combination of data sources ensures that the majority of moves are covered for England and Wales.  However, given that not all moves are covered there will be some error around these estimates to the level of detail provided; that is, age groups within local authorities. 

Understanding internal migration is an important element in estimating overall estimates of the population at local and national level, building upon known birth and death statistics and estimates of international migration.

Key Messages:

• Internal migration from within Britain is the primary factor in Somerset’s increasing population.
• Somerset experiences a net flow of migrants from other parts of England and Wales, especially from some neighbouring districts, the South East and London.
• However, there is a consistent net flow of 16-24 year-olds out of Somerset. This has implications for the future economic development of the county as there is a dwindling resource of young people to generate income.
• Amongst 18-20 year-olds, it is even more acute, with notable net flows to London and university cities such as Plymouth, Cardiff, Bristol and Bath, highlighting the impact of having no university in Somerset.

Detailed analysis for Somerset

The 2016 mid-year population estimate for Somerset released in June 2017 is 549,447, indicating a rise of 4,057 year-on-year. A large proportion (87%) of this estimated gain is attributed to net inward migration, much of it from other parts of Britain. In this respect, Somerset follows a similar pattern to that of similar rural counties in the South West.

In the year ending June 2016, there were an estimated 39,720 people moving into or out of Somerset, a rate of approximately 72 per 1000 population. This is in line with similar counties such as Herefordshire (69), Cornwall (68) and Shropshire (71).

The net flow into Somerset (the number coming in, less the number going out) from other parts of the UK increased to 3,896. Each of the five Districts experienced a net flow into its borders (see chart below)

Net Internal Migration, Somerset and Districts

Source: Office for National Statistics

Please note that about a quarter of internal migration (6,246 people) for the five districts occurs within Somerset; in other words, only between these districts.

The overall figures also mask notable differences between age groups. In particular, last year saw record net inward migration of 45-64 year-olds and those aged 65 or older into the county. Meanwhile, there has been a consistent net flow out of Somerset amongst 16-24 year-olds. However, at 1,498 in 2015-16, this was below the peak level of 2,010 in 2011-12 (see below)

Internal Migration by Age Group, Somerset

Source: Office for National Statistics

The situation with 16-24s is driven largely by the 18-20 age group in particular, amongst whom there is a net flow out of Somerset of 2,100. This is probably because there is no university based in the county. Amongst this age group, the largest flows out of Somerset are to university cities such as Plymouth, Cardiff, Bath and Bristol.

The 2011 Census confirms Somerset's status as a net 'exporter' of university-age students. However, the county is a net 'importer' of school-age students; in 2011 the population of 11-17 year olds increased by 1,700 during term-time. Overall, this means that Somerset’s estimated resident population was around 3,700 higher during school and university holidays

Whilst there is anecdotal evidence that many who leave for university do return in later life, this internal emigration does contribute to Somerset’s decreasing number of working age people as a proportion of the population. This, in turn, poses a challenge to filling local job vacancies arising from future economic regeneration.

Where do they go to and come from?

Apart from the northernmost areas, there is a net migration from all English regions into Somerset (see first map below). The largest single contributor is South East England, extending from Oxford and Southampton to Kent. 

Amongst the 16-24 age group, there is a net migration out of Somerset to all parts of England and Wales. In 2015-16, London and the South West remain the primary net destination regions (see second chart below).

For detailed tables of these internal migration flows, please go to the ONS website.

The Office for National Statistics also has an interactive map tool showing the all-age flows into and out of each Local Authority in England and Wales.

See also:

• International Migration