This Is How Much The British Population Is Expected To Grow

There are going to be lots more people, and they'll be a lot older, according to official projections.

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The Office for National Statistics (ONS) has predicted that the British population will reach 70 million by 2027, and 80 million by 2060. That's up from about 64 million now.

ONS / BuzzFeed / Via ons.gov.uk

A large percentage of that growth is expected to be from immigration.

ONS / BuzzFeed / Via ons.gov.uk

"Natural growth", i.e. there being more births than deaths in the existing population, is expected to tail off over the next few decades.

The 2014-2015 levels of net migration are dramatically higher than those predicted for the years to come, presumably because of the current refugee crisis, which the ONS seems to assume will come to an end in the next year or two.

Weirdly, despite the natural growth, the number of babies being born is not expected to be enough to replace the existing population.

ONS / BuzzFeed / Via ons.gov.uk

This is because the ONS assumes that people will continue to live longer. People born after 1922 and before 1939 are living into their eighties more than any previous generation, so even though there are not enough babies being born to replace their parents, the population is still growing because people are taking longer to die.

The slowing birth rate and increased longevity have another knock-on effect: an ageing population.

ONS / BuzzFeed / Via ons.gov.uk

The average (median) age of the population is expected to go up from 40.9 last year to 42.9 in 2039. That may not sound all that dramatic, but it translates into a major leap in the percentage of the population who are over the current retirement age – up from 19.1 to 22.3.

Meanwhile, the percentage of the population who are of working age is expected to go down. At the moment, there are more than three working-age people for every retirement-age person. By the end of the century, that ratio will – if the ONS's predictions are borne out – be barely two to one, making it ever harder to support pensions.

However, the projections need to be approached with caution. The ONS itself says they are not forecasts and do not take into account the effects "future government policies, changing economic circumstances, or other factors might have".

It's worth noting that their previous projections have been significantly off.

ONS / Via researchbriefings.files.parliament.uk

The 1971 projection overestimated the 2010 population by around 4 million, while the 1981 undershot by about the same margin. Later projections have been closer – the 1991 and 2001 estimates undershot by "only" about 2 million – but it's easier to make predictions over shorter periods. There's just less time to be wrong in.