Want the best of The Telegraph direct to your email and WhatsApp? Sign up to our free twice-daily Front Page newsletter and new audio briefings. The latest DfE statistics, which look at the make-up of the school population across England, also reveals that one in three of the nation’s primary school children are from a minority ethnic background. More than one in five primary-age children do not speak English as their first language.Geoff Barton, General Secretary of the Association of School and College Leaders, said that schools have had to make huge budget cuts over the past three years to cope with financial pressures.“Many have had no choice other than to cut teaching posts which inevitably means larger classes,” he said.”No school wants to do this because it means teachers are less able to give individual support to pupils and larger classes drive up workload pressures. But the funding crisis has left them in an impossible position.” Super-sized classes are at the highest level on record, official figures show, as secondary schools begin to feel the effects of a migrant-fuelled baby boom.Eight per cent of secondary school classes now have over 30 children, which is the highest proportion since the Department for Education (DfE) started collecting figures for its annual school census in 2006. In 2006, 7.5 per cent of classes had over 30 children, which had dropped down to 5.8 in 2014 but has been climbing up steadily since then.The average secondary school class size in 2018 was 21.2 students, the new data shows, which is the largest since 2007. There is now the equivalent of one extra pupil in each class, compared to five years ago.Overall, there are now 66,000 more children in the nation’s schools compared to the same point last year. While some of this increase was in primaries, most was in secondaries, which have seen numbers rise by 35,400 in just a year.The hike comes amid a boom in pupil numbers caused in part by a rise in the birth rate in the early 2000s, that is now making its way through to secondary schools.While direct immigration has little effect on pupil numbers, higher birth rates among immigrant communities has been a contributing factor, according to DfE forecasts. “Alongside this we are spending £23 billion by 2021 to ensure every child regardless of their needs, background or circumstances has access to a good school place.” The Local Government Association spokesman urged ministers to give councils powers to force schools to expand if necessary.A spokesman said this would only need to occur “if local agreement cannot be reached voluntarily where this is in the best interests of new and existing pupils”.School standards minister Nick Gibb said: “Although we have more children in our education system than ever before, the average primary class size is still 27.1 and the average secondary class size shows little change at 21.2.”This is thanks to the 825,000 new school places we have created since 2010 the largest expansion of new school places since the 1970s.