The Daily Telegraph has obtained data from the Department for Children, Schools and Families illustrating the impact of high levels of immigration on the education system.
The figures show that in a total of 1,338 primary and secondary schools—more than one in 20 of all schools in England—children with English as their first language are in the minority.
In 600 of these schools, fewer than a third of pupils speak English as their first language.
The disclosure led to warnings that the rising number of foreign pupils without a decent grasp of English was putting intense pressure on teachers and undermining education standards.
The figures have fuelled demands from teachers’ leaders for more money to help meet the costs of teaching foreign-born children.
Teachers’ unions said educating a single non-English-speaking pupil could cost as much as £30,000 a year.
Coping with large numbers of foreign children risked undermining the quality of teaching given to all pupils, they said.
Philip Parkin, the general secretary of the Professional Association of Teachers, said rising levels of immigration and a lack of multi-lingual teaching staff were “providing serious challenges” for schools trying to maintain standards.
Dealing with non-English-speaking children “makes it much harder to deliver the curriculum”, Mr Parkin said.
“Schools that are in that position need considerable support in order to give those children help with English and help with our curriculum.
“The Government needs to be looking at funding the employment of teachers or teaching assistants, in addition to the staff they have, who are bilingual or multilingual.”
Last month, the National Association of Head Teachers said some schools were struggling to cope with the influx of foreign pupils.
Mick Brookes, the union’s general secretary, told a Lords committee that the situation was “out of control”.
A rush of migrants into an area can “strain or even break the resources of the school”, he said.
Last night, Mr Brookes said the latest figures proved the case for putting additional resources into the areas dealing with large numbers of non-English speakers.
“There are children who cannot speak the language,” he said. “Others are refugees who may have witnessed some horrible things.
“These children may not just need support to speak English, but often they require counselling to talk them through the trauma they have witnessed.”
Data from the Department for Children, Schools and Families show that in 574 of the 17,361 primary schools in England, children without English as a first language make up between 51 and 70 per cent of all pupils.
Another 569 primaries have more than 70 per cent who count English as a second language.
In 112 of the 3,343 secondary schools, children without English as a first language make up 51 to 70 per cent of all pupils. In another 83 secondary schools, the proportion is above 70 per cent.
The total number of schools where pupils with a first language other than English make up at least 51 per cent of the population is 1,338.
Following patterns of immigration, children who do not speak English as a first language are heavily concentrated in certain areas of the country, especially London.
The 20 councils with the highest concentration of non-English speaking children are in London.
In the borough of Newham, nine out of 10 schools have a non-English first language majority. The same is true of a third of schools in Leicester and in Blackburn, and a quarter of schools in Birmingham.
Gordon Brown last week repeated calls for immigrants to learn English, but critics say he is not doing enough to fund proper language teaching for immigrant children.
David Davis, the Conservative shadow home secretary, accused the Government of failing to meet the costs of its immigration policy.
“We have been warning the Government for years now of the consequences for schools of the very high rate of immigration,” he said. “This shows how many schools will face real difficulties.”
The Government said last night that it was properly funding schools facing extra costs from children struggling with English.
A DCSF spokesman said: “We have listened to the unions’ concerns and are increasing funding in the Ethnic Minority Achievement Grant to £206 million by 2010.
“We have also introduced new guidance for teachers to work with new arrivals. There’s actually surplus money in the school system to deal with any ‘exceptional circumstances’.”
But even Labour MPs have expressed concern that the Government is failing to keep up with immigration.
Phyllis Starkey, the Labour chairman of the communities and local government committee of MPs, last week warned Mr Brown that funding delays risked inflaming “community conflict”.
Many of the pupils without English as their first language are the children of the 600,000 eastern Europeans who have come to Britain since the European Union’s eastward expansion in 2004.
Official statistics last week showed that one in five births in Britain last year was to a woman from overseas.