ISSUES
: Our Changing Population
Chapter 1: Population in the UK
12
projected to increase by almost
ten million between 2012 and
2037 – from 63.7 million to 73.3
million, an increase of 15%. In this
demographic scenario, the UK
population will reach 70 million in
2027. The different net migration
levels assumed in the high migration
and low migration variants (±60,000
per year) lead to a variation after
25 years of ±1.7 million people – or,
in relative terms, a 5% difference
between the low migration and
high migration variant. Projected
population size in 2037 according
to the long-term ‘balanced’ net
migration variant (which assumes
convergence of net migration to zero
towards the end of the projection) is
only marginally lower (-0.5 million)
than in the low migration variant.
In the zero migration variant, the
projected population size reaches
67.5 million in 2037, or 7.9% less
than the principal projection.
Net migration
accounts for over two-
thirds of projected
population growth
The UK population is projected to
rise both because of positive natural
change and because of positive net
migration. Population growth in the
absence of further migration would
total 3.8 million, equivalent to 39.4%
of the total increase in the principal
projection. However, the size of the
UK population with no additional
net migration would level off at 67.5
million over the next three decades
and would eventually decline if the
projections are carried forward
beyond mid-century. In the principal
projection the cumulative net inflow
of new migrants accounts for
43.5% of total population growth,
i.e. an addition of 4.2 million. The
additional (indirect) contribution of
post-2012 immigrants to natural
change until 2037 is estimated at
1.6 million, i.e. 17.1% of projected
population growth. In total,
therefore, 60.6% of the expected
increase in the UK population is
attributable, directly or indirectly, to
future net migration. It should also
be emphasised that, while these
calculations are based on the same
assumptions about future fertility
and mortality rates irrespective of
the assumed level of net migration,
fertility and mortality rates for
recent migrants are likely to differ,
to some extent, from those for the
long-established population – e.g.
assuming higher fertility rates for
post-2012 immigrant women would
imply a larger indirect contribution
of migration to natural change.
References
Dormon O. “Childbearing of UK
and non-UK born women living in
the UK - 2011 Census data.” ONS,
London, February 2014.
Herm A. and M. Poulain.
“International Migration Data as
Input for Population Projections.”
Working Paper 20, Joint Eurostat/
UNECE
Work
Session
on
Demographic Projections, Lisbon,
28-30 April 2010.
ONS. “Methodology Guide for Mid-
2011 Population Estimates, England
and Wales.” ONS, London, 2012.
ONS. “Revised Annual Mid-year
Population Estimates, 2001 to
2010.” ONS, London, December
2013.
ONS.
“Background
and
methodology: 2012-based national
population projections.” ONS,
London, November 2013.
Tromans N, E. Natamba, and J.
Jefferies. “Have Women Born
outside the UK Driven the Rise in
UK Births since 2001?” Population
Trends 136 (2009):28-42.
19 February 2014
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The
above
information
is
reprinted
with
kind
permission from The Migration
Observatory. Please visit www.
migrationobservatory.ox.ac.uk
for further information.
© The Migration Observatory 2015
