New census data on London's population figures underestimates the number of people living in the capital, council leaders have warned.

London Councils said the number of Londoners is likely to have been significantly undercounted in the census due to the number of people who moved out of the city to a family home during the COVID lockdown.

The census found London's total population in March 2021 was almost 300,000 (3%) lower than the Office for National Statistics' (ONS) previous population projection for 2021, with some boroughs' figures almost a quarter (24%) lower.

London Councils, which represents the capital's local authorities, warned undercounting the capital's population could have a major impact on future funding allocations for public services.

Chair of London Councils, Georgia Gould, said: ‘It's a bitter irony that it's often the Londoners with the lowest census response rates who most depend on local authority support.

‘We are concerned that, without looking at the data in the context of the challenges the pandemic created, Londoners will lose out.'

In Westminster alone it is estimated that around 30,000 residents may be missing from the census data.

Westminster City Council's cabinet member for finance, David Boothroyd, said: ‘There can be no escaping the fact that the information gathered by the census does not represent Westminster's actual population.'

A spokesperson for the ONS said it had ‘full confidence' in its census estimates.