Parents from ethnic minorities who are unhappy with their children's education have long regarded supplementary schools as an important alternative. But now the schools, usually run by volunteers at evenings and weekends, are to be brought into the mainstream.
"Working in isolation is not an option," said Kevin Brennan, the junior minister for children, in a parliamentary debate. "We need these schools to become more closely entwined within the fabric of our education system."
There are estimated to be around 5,000 such schools, ranging in size from 10 children to hundreds.
Their history is obscure, but there is evidence that one opened in Leicester in 1896. The movement really took off in the 1950s, when immigrants set them up to keep their offspring in touch with their home language and culture.
There is increasing evidence that such schools can help raise results, and they fit neatly into the Government's extended schools drive.
And it seems that teenagers actually like attending them - even on Saturdays. Steve Strand, a reader in education at Warwick University, carried out the first national survey soliciting pupils' opinions. The survey covered 63 schools that received government grants.
"You'd think if you asked kids to give up Saturdays and go to school, you'd get a resounding 'No'," he says. "Were parents pressing them into it? It doesn't seem to be the case." His research found that, overall, pupils' attitude was more positive than their attitude towards mainstream education. While attitudes to mainstream schools deteriorated with age, attitudes to supplementary school did not.
Last year, ContinYou, which helps schools provide extended services, was charged with managing the new National Resource Centre for Supplementary Education (NRCSE), funded by the Department for Children, Schools and Families and the Paul Hamlyn Foundation. The centre provides support for the supplementary schools and is campaigning to raise their profile, secure better funding and encourage mainstream and supplementaries to work together.
The centre's website details examples of best practice, including the Ishango Science Club, which has helped raise African-Caribbean pupils' test scores in Birmingham, and the Leeds Chinese Community School, which started small in 1966, but now has more than 150 pupils.
One of the most successful projects is based at the City Academy in Bristol. The Mainstreaming Supplementary Schools Support Project differs from most other supplementaries because it is a hybrid school and community project, using teachers and community volunteers, managed by school staff recruited from the target communities.
On Saturdays, the school holds lessons in English, maths and science for Muslim pupils of Bangladeshi, Pakistani and Somali origin, and a separate school for African-Caribbean pupils, which includes an academic mentoring project. There is also a primary project. In total, 600 pupils from 13 schools are supported.
The results are impressive: 50 per cent of its pupils achieved five good GCSEs, even though only 35 per cent had been predicted to do so.
Ahmed Abdi, 15, says: "It has helped me a lot. I was predicted Ds and Cs, now I'm predicted Bs and As. I definitely want to go to university. Before, it was looking a bit bleak; now it's looking better."
Hiqab Nour Elmi, 16, is a Somali who arrived in Bristol from Germany in Year 9, speaking almost no English. She can now speak three languages, starts French this year, and wants to become a teacher.
"You make new friends," she says. "In my class, there is only one girl from my school. She's Asian and at first I hung around with the Somalians because I didn't speak English, but by the end we all mixed with everyone."
Ken Fyfe, director of community engagement and partnerships at City Academy, says the mainstreaming project developed because of an influx of Somalis who needed help with English.
"The objective is that students feel classes are not organised by the school - they're organised by the community," he says. "The atmosphere is different. The teacher is a guest of their community and it is not compulsory to go. Peer pressure - a huge thing in schools - is taken away. Pupils don't feel they have to stand up for their ethnic group."
Ray Priest, head of the academy, says: "We are serious about transforming achievement. You can't do it within your own school alone. To make a large difference needs mum and dad; it needs the community. In August, if the results are fantastic, the school gets the credit. Why not share that credit?"
But some fear that tapping into supplementary schools will undermine their own schools and leave pupils worse off. The think tank Civitas has argued that "regulation creep" through things such as the voluntary quality code, which is being introduced by the NRCSE, could turn supplementary schools into little more than booster classes, destroying their appeal to pupils.
Nick Cowen, research assistant at Civitas, says: "The most important point to get across is that variation in the sector is wide and some schools are a lot better than others. Looking at why some do particularly well, it might be because the state is not involved. Perhaps part of the reason these schools are good is because they are independent."