More than three quarters of babies born in parts of England and Wales last year were to foreign mothers, official figures show.
Data from the Office for National Statistics reveals 613,936 babies were born in the two home nations in 2020 – a 4.1 per cent drop on 2019 and the lowest figure since 2002.
Nearly a third of babies were birthed by women who were born outside the UK – the highest since records began four decades ago.
In the most ethnically-diverse parts of England – the top nine of which were in London – the figure was three times as high.
In Brent 76 per cent of newborns had a foreign mother, followed by Harrow (75 per cent) and Newham (74 per cent).
Most of the foreign mothers were born in Pakistan and Romania – around one in 11 – or Poland – around one in 12.
Meanwhile, the total fertility rate – the average number of children each woman has – reached a record-low and birth rates dropped among all age groups.
The figures do not yet show the impact of the coronavirus pandemic – which experts told MailOnline may push the birth rate lower – as the babies born in 2020 were conceived before the crisis hit the UK.
But a baby boom could also be on the way, after NHS figures revealed earlier this year that the number of antenatal appointments booked in the last three months of 2020 was the highest seen in five years.
The graph shows the estimated total fertility rate – how many babies each women has on average – from 2004 to 2020. The gap between babies born to to UK (dark blue line) and non-UK born women (light blue line) widened for the third year in a row. The fertility rate among women born in the UK dropped to 1.58, while it increased to 1.98 among those born elsewhere
The graph shows the 10 most common countries of birth for women who gave birth in the England and Wales, but were born elsewhere, in 2011, 2014, 2017 and 2020. In the most recent year, Pakistan became the most common country of birth for non-UK mothers
The graph shows the 10 most common countries of birth for fathers who were born outside the UK, in 2011, 2014, 2017 and 2020. In the most recent year, Pakistan remained the most common country
The number of babies born in England and Wales in 2020 was 4.1 per cent lower than 2019 and the lowest number rerecorded in 18 years.
The ONS warned the figure is likely a 'small underestimate' of the actual number delivered, due to birth registrations delays caused by the pandemic.
Since the most recent peak in 2012 – when 729,674 babies were born – the number of births has fallen by 15.9 per cent.
And the total fertility rate dropped to 1.58 children per woman – the lowest since records began in 1938. The figure marks a drop of 4.2 per cent on one year earlier and is 3.1 per cent lower than the previous all-time low of 1.63 children per woman.
The ONS cited improved access to contraception, lower levels of fertility