The number of people in Britain may rise by more than a fifth to reach close to 80 million within 25 years, an official report estimated today.

It said the population could be just over 79 million by the year 2039 if high levels of immigration persist and the pace of increase in life expectancy and birth rates continue to go up.

The projections from the Office for National Statistics point to the highest level its experts believe the population could reach. However they are based on immigration figures from two years ago which are far lower than the rate of immigration recorded over the past two years.

The Office for National Statistics said the population could be just over 79 million by the year 2039 if high levels of immigration persist

They drew fresh warnings yesterday that the country faces severe strains on essential services and resources, as well as deep public disaffection, unless politicians begin to bring down record immigration rates.

UK COULD STOP TEN TIMES MORE TERROR SUSPECTS FROM ENTERING THE COUNTRY IF IT LEAVES THE EU, CLAIMS JUSTICE MINISTER Dominic Raab (pictured delivering a speech in central London today) said Britain could stop ten times as many criminals and terror suspects if it leaves the EU Britain could stop ten times more criminals and terror suspects from entering the country if it leaves the EU, a justice minister declared today. Dominic Raab launched a scathing attack on current EU rules, which he said allowed terror suspects to 'waltz' into Britain because they have a 'free pass' to roam around Europe under freedom of movement rules. But UK authorities often had were often powerless to bar EU criminals even when it had intelligence that somebody was linked to terrorism because the bar for denying them entry was set so high under Brussels rules. He compared the 6,000 EU nationals refused entry since 2010 to the 67,000 people from non-EU countries who were barred from entry. The contrast in figures was 'undeniable' proof that regaining control of our borders would be a 'valuable defensive tool' in protecting Britain from future terrorist attacks, Mr Raab said. In a speech in central London today, he warned the 'unyielding' freedom of movement rules was a threat to Britain's security. It 'effectively means that we're importing risk with reducing means, or finite resources within which we can address and monitor and keep an eye on,' he said, describing it as a 'very serious chink in our security apparatus and was 'a direct result of the EU'. Mr Raab said: 'This week those campaigning to stay in the EU pointed out that 6,000 EU nationals have been turned away from the UK since 2010. That is absolutely right. 'But, 67,000 non-EU nationals were refused entry. That is ten times the number, even though we've had double the number of European nationals visiting the UK over that period. 'It is undeniable on the basis our our own practice, on the basis of the very statistics cited by the Remain campaign, that being outside the EU would result in stronger preventative checks at the UK border.' Advertisement

The ONS published its full projections of expected future population size the day after the Daily Mail disclosed that 1.6 million immigrants are thought to have moved from other EU countries to Britain inside a decade.

Figures for National Insurance numbers given to new arrivals from the EU who need them to work or claim benefits have been running at more than double the recorded number of EU immigrants since 2010. But ministers have declined to release information on the number of NI numbers which are ‘active’ – in other words are currently being used to pay tax or claim benefits – so real numbers remain obscure.

The new ONS estimates said that net migration, the number of people by which immigration swells the population each year, is expected to fall to 185,000 a year after 2020 and remain at that level. At this rate, and at predicted birth and life expectancy rates, they suggest that the population will go up by nearly 10 million by 2039, from 64.6 million in 2014 to 74.3 million.

However net migration figures passed the 300,000 a year mark in the last three months of 2014 and have continued above that level since. The most recent net migration figure, for the 12 months which ended last September, put net migration at 323,000 for the year, with no sign of a significant fall.

The ONS projections put the highest possible level for long-term net migration at 265,000, nearly 60,000 a year below the current level. At this rate, and if birth rates and life expectancy also hit high levels, they say that by 2039 Britain’s population will be 79,090.

The estimate means a population increase of more than 22 per cent. In terms of numbers, it amounts to just under 14 ½ million, close to 600,000 a year over the 25-year period between 2014 and 2039.

Continued high immigration is likely to bring with it high birth rates, because immigrants are mainly young people who are more likely to have children than other sections of the population. Life expectancy has gone up over the past 40 years at a rate of 1.9 per cent a year for men and 1.5 per cent a year for women, and the highest immigration expectations at the ONS are based on the possibility that this will rise to 2.4 per cent a year.

The ONS said that under its main future population estimate, putting 2039 numbers at 74.3 million, 68 per cent of the population increase will be a result of immigration.

Just over half the extra numbers of nearly 10 million envisaged under this projection will be immigrants, while 17 per cent will be a result of additional births and deaths because of immigration.

The high projections brought new warnings that the Government, which has failed to live up to David Cameron’s promise to bring net migration down to 1990s levels of less than 100,000 a year, should respond to deepening public concern.

Critics say that immigration is bringing growing pressure to bear on housing, transport, power, water, education and health services, as well as putting social cohesion at risk and reducing the wages of lower-paid workers.

Lord Green of the Migration Watch UK think tank said: ‘For far too long the Government machine has had its head in the sand about the sheer scale of likely population growth. We must now face the possibility that the high migration scenario will turn out to be the correct one.

‘This would mean building the equivalent of the city of Liverpool every year for the next 25 years.’