We now have more robust figures on the size and characteristics of Barnet’s population.

But how do they compare to estimates which are used by decision makers in central and local government to understand their communities’ needs?

Mid-year population estimates are produced annually by the Office for National Statistics and are based on the most recent census.

The ONS rolls forward information from registers for births, deaths and migration surveys to produce each year’s estimate – but it means the further away from the census, the more uncertain they are.

ONS statisticians estimated there were 399,007 people of all ages living in Barnet as of mid-2020 – above the 2021 census figure of 389,300.

But London Councils, the umbrella body representing all 32 boroughs and the City of London Corporation, said the capital’s population is likely to have been “significantly undercounted”, in part due to some people temporarily relocating themselves during the pandemic.

The census data, a snapshot of society across England and Wales on March 21 2021, suggests London’s total population was just over 200,000 (2%) lower than the previous population projection.

Data from the 2021 census tells us there were 56,100 (14.4%) over-65s living in Barnet, showing little difference to the 58,170 (14.6%) estimated by the ONS.

There are reportedly fewer males in Barnet than estimated by the ONS – 2021 census results revealed 188,400 males (48.4%) were usual residents on census day, while the mid-2020 prediction was 198,961 (49.9%).

The latest estimates suggested there were 200,046 (50.1%) females in the area, but in March last year, 200,900 (51.6%) said Barnet was their home.

The ONS says population statistics are “vital in making a range of decisions and informing public debate”.

During the coronavirus pandemic, estimates have been used to measure vaccine uptake at a national and regional level, while they are also used to measure unemployment rates, forecast pensions and make decisions about local services – such as the number of school places of the provision of health services for an ageing population.

The 2020 mid-year population estimate for England and Wales as a whole stood at 59.7 million – very close to the 2021 census figure of 59.6 million.

The ONS noted that population change in certain areas “may reflect how the coronavirus pandemic affected people’s choice of usual residence on census day”.

“These changes might have been temporary for some and more long-lasting for others,” it added.

Georgia Gould, chair of London Councils, said: “Census 2021 took place during the extraordinary circumstances of the Covid-19 pandemic and a national lockdown, so this snapshot data must be treated with extreme caution.

“Accurate census data matters for Londoners because it helps determine government funding allocations to local authorities. Billions of pounds for frontline services are at stake.”

She added that even small inaccuracies in population counts can “seriously undermine” future service provision, and cautioned that Londoners could end up losing out as a result.

This is one in a series of reports on Census 2021. Previous articles looked at Barnet’s ageing population and the growth in numbers of local residents.