The number of Charedi children may have been undercounted by a third in the last Census, according to a new report.

As many as 3.500 Strictly Orthodox children up to the age of 15 may have left out of the tally for Jews in England and Wales, the Institute for Jewish Policy Research says.

JPR executive director Jon Boyd said, “It raises concerns about the accuracy of the data regarding the Charedi community in Britain, which is key for planning in that sector, and the larger British Jewish community as a whole, as these absences have implications for determining Jewish demographic trends more generally.”

The report, written by JPR senior research fellow David Graham, put the undercount at up to 35 per cent.

It “supports a common contention that Census form length was a key cause of this undercount, assuming children are generally entered onto the form from oldest to youngest”, he wrote.

He added: “If, as we suspect, they are missing because they were not included on household Census forms, it means they are not just missing from the Jewish count but are absent from the Census entirely. This is a doubly concerning outcome given that this is an especially vulnerable group.”

Another reason for the undercount was that the Census took place during the pandemic in March 2021, which might have affected Charedi responses.

Overall, the Jewish population in England and Wales rose by 2.4 per cent  from 265,073 in 2011 to 271,327 in 2021 - mainly due to the growing Charedi communities with their large families.

The statistic is based on the numbers who respond to the voluntary question on religion in the survey.  (As yet, the smaller number of Jews who voluntarily identify as ethnic, not religious, has yet to be counted).

Although the Census does not identify the denomination of Jews, researchers can estimate the Charedi population by assessing the areas where there is a strong Charedi community such as Salford, Gateshead, Hackney and Haringey.

But comparing the Census data with birth announcements in Charedi newsletters and government statistics on enrolment in Jewish schools, JPR has found that the Census figures are lower than expected.

The undercount was “greatest among the youngest children”, the report stated.

The discrepancies also varied according to region. Only 66 per cent of Strictly Orthodox Jewish children may have been picked up by the Census in Salford, 73 per cent in Hackney and 85 per cent in Gateshead.