Department for Education data shows that two secondary schools in Luton were at or above full capacity as of May 1 last year with the busiest being Cardinal Newman Catholic College, which had 1,650 school places but 1,682 children on its roll – 2% over capacity.
In 2018-19 – the most recent comparable year due to coronavirus pandemic restrictions – there was one overcrowded school.
It meant 3,134 pupils in the area were affected by overcrowded schools last year – among around 880,000 nationwide.
The Association of School and College Leaders said a record rate of overcrowded schools nationally is being driven by increased demand for
The ASCL said a large contingent of children is moving into secondary education, and though local authorities are experienced at forecasting demand, it is not an exact science.
Geoff Barton, general secretary of the organisation, added: “The increasing demand for secondary places is complicated by perceptions linked to Ofsted reports with higher-rated schools often heavily oversubscribed and significant spare capacity at lower-rated schools.
“It drives a vicious cycle with improvement harder to secure in schools which face the greatest challenges.
"The current approach needs a rethink so that it is more supportive and less punitive, and so that every family has access to a good local school place.”
The Education Policy Institute said overcrowding increases the average class size – placing additional demands on teachers – and has implications for admissions.
Jon Andrews, head of analysis at the EPI, said more pupils means schools are more likely to be oversubscribed leaving pupils at less preferred schools or going through the appeals and waiting list systems.
He added: "Our research shows that pupils from disadvantaged backgrounds are less likely to be successful than others via these routes."
Just 17% of English primaries were at or over capacity last year – the lowest rate since records began in 2009-10.
This included two in Luton – up from one in 2018-19.
Mr Andrews said the number of pupils attending primary schools, peaked in 2019 and is expected to continue to decline.
A DfE spokeswoman said: “The vast majority of pupils will be offered a place at one of their preferred schools this coming year.
"Pupils are also now more likely to have a place at a good school now – with 87% of schools rated good or outstanding now compared to 68% in 2010.”
A spokesman for Luton Council said: “In the secondary sector, Luton’s Year 7 intakes are projected to remain relatively stable for the next six years.
"Pupil places created from current and upcoming housing developments are likely to be offset by falling pupil numbers moving into the primary sector. In the discharging of our statutory duties for having sufficiency of school provision in response to local needs, it is clear that Luton has sufficient capacity overall and this is set to be the case for the foreseeable future.
"Having heavily oversubscribed, popular schools is not unique to Luton; many other LAs struggle to match local supply and demand for the most popular schools, whilst still ensuring access to provision for all children within their area.”