Parents with children at Jewish primary schools in London will be asked to take part in a survey to help gauge future demand.

Commissioned by Partnerships for Jewish Schools (Pajes), the survey is designed to find out what proportion of places are likely to go to siblings of current pupils.

According to figures recently obtained by the Board of Deputies from 26 London Jewish primaries, schools have filled 96 per cent of their available places this year.

“We pretty well have a full system,” said Pajes executive director Alastair Falk. “There is the odd spare place when a family goes on aliyah or moves.”

The sibling data will give parents and schools a better idea of future pressure on places. Analysis of the 2011 Census results will also provide overall numbers of Jewish children of school age in different areas. “We should be able to get a more accurate picture of the real percentages of people applying to Jewish schools,” Mr Falk said.

Although the competition for places remains fierce in many schools, the planned opening of new Jewish primaries has raised concerns of future vacancies, leading to an increasing intake of non-Jewish pupils.There is no breakdown of non-Jewish children already at Jewish primaries in the capital.

But the current scramble for places has also put admissions policies under closer scrutiny, in some cases prompting complaints to the Office of the Schools Adjudicator, the body regulating entry rules.

Governors and head teachers of Jewish schools were recently briefed by OSA chief adjudicator Elizabeth Passmore at a meeting arranged by the Board.

Education law expert Richard Gold, who also spoke at the event, advised primaries to leave some reception places open for children who had not previously attended the school nursery.