The UK population is set to grow by five million people in ten years, despite death rates being projected to overtake birth rates in that time.

All of the forecast population growth is due to migration.

Britain is expected to take in a total of 494,000 more people a year on average over the next decade than the amount who leave, analysis by the Office for National Statistics (ONS) reveals.

There are expected to be about 30,000 more deaths than the number of children born over that time.

Net migration in 2023 was 906,000. However, with recent changes to student visas and less current movement of Ukrainians and other refugees, it's projected to decline significantly from current high levels - though still remain at a higher rate than any year prior to 2022.

Of course, future global shocks are impossible to predict and could impact migration.

Despite the fall, it would mean the UK having the highest migration rate in Europe by 2029 (excluding countries with populations smaller than 500,000), overtaking the Netherlands, Ireland, and countries that border Ukraine.

The figures for other countries are based on UN measures, which are slightly different in methodology to those in the UK.

That would be the first time on record, going back to at least 1950, that the UK has had the highest net migration rate in the continent.

The vast majority of migrants to the UK tend to be of working age, which is good for the economy in the short term.

However, the projections show that the age profile of the country will continue to get older, posing potential problems in years to come in affording to support those of pension age.

The Office for Budget Responsibility (OBR) recently suggested that total welfare spending on pensioners this year would be just over £150bn - more than the budgets of the Home Office, the Ministry of Defence, and the Department for Education combined.

Jennifer D. Sciubba, president and CEO of the Population Reference Bureau in Washington DC, told Sky News that economies could be at risk if governments fail to adapt to the changing population landscape: "The biggest threat to stability is for decision makers to put their heads in the sand and ignore that the demographic trends have fundamentally shifted.

"If they're still operating under the assumption that economic growth will resemble what it did in the past when population growth was assured then they are putting their economies and societies at great risk."

How reliable are the numbers?

Arkadiusz Wisniowski, professor of social statistics and demography at the University of Manchester, told Sky News that the ONS's estimates are "a little bit optimistic that it will fall that dramatically".

He said the UK is unlikely to suddenly become less attractive to migrants and that the government is unlikely to suddenly implement very harsh policies to stop migration.

The most significant recent change in policy towards legal migration was the previous government making it more difficult for economic migrants to bring dependents - spouses or children - with them into the country.

That is expected to bring down migration to the UK, but the UK economy as it currently operates still requires some level of immigration to fill jobs, particularly given the long-term issue of declining birth rates.

On this point, Prof Wisniowski noted that there were 1.4 million visas issued in 2023.

"None of these people have cheated the system, and there is a need for them in the country because either there was a job for them or they were students internationally who we also need desperately.

"[Reaching the projected 340,000 net migration] would rely on external factors to be achieved, for example, the end of the war in Ukraine and people returning there in large numbers, or other countries suddenly becoming significantly more attractive to migration.

"Perhaps Donald Trump imposes very harsh tariffs on Europe and the UK may become closer with the EU. The world is an interconnected system and we cannot really look at one country in isolation."

The reality of net migration in the last few years, since Britain's departure from the EU, has exceeded even the highest forecasts from previous years.

If net migration reaches the highest level currently believed to be likely by the ONS, the UK population will be 73.2 million by 2032 and have grown by a further nine million to 82.2 million by 2050.

However, if net migration follows a slower trajectory at the lowest level currently believed to be likely, the population will be 70.9 million by 2032 and will have then fallen to 70.7 million by 2050.

These figures all assume that death rates and particularly birth rates - which have been falling in recent years to levels below what was projected - also don't change much from what's currently predicted.

Professor Wisniowski told Sky News that fluctuations in migration levels make the biggest impact on population levels, because death and birth rates are more stable and relatively easier to predict.

All told, there's a total difference of almost 17 million people between the highest and lowest population projections for 2050, given all possible combinations of birth rates, death rates and migration levels, from 68.2 million at the low end to 84.8 million at the top.

A Home Office spokesperson said the government will soon "set out a comprehensive plan to restore order to our broken immigration system".

"We will link our immigration, skills and visa systems so we can grow our domestic workforce, end the reliance on overseas labour and boost economic growth."

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The ONS says that the projections are "based on the latest mid-year population estimates for each UK country and the latest births, deaths, and migration data. Projections are not forecasts and will differ from actual future outcomes to a greater or lesser extent.

"Patterns of births, death, and migration can change and are influenced by many factors, such as geopolitical, economic and policy change. It is not possible to consider all possible factors or to know in advance what impacts these might have.

"Therefore, the projections do not attempt to predict the impact of events such as the UK leaving the EU or the lasting effect of the coronavirus pandemic.

"However, the projections of people of State Pension age (SPA) do reflect future changes under existing legislation."