A Saturday school for literacy, run on a shoestring from a converted shop, has helped improve educational standards for children from some of the poorest homes, according to a study.

Children attending the two-hour weekly sessions performed significantly better in reading and English tests at the age of 11 than others from similar backgrounds. They are also more likely to reach the national benchmark for English and maths during the last year of primary education.

The Butterfly school, founded in 1999, operates on an estate in Queen’s Park, northwest London, with a reputation for high crime and antisocial behaviour. The area has the highest rate of child deprivation in the country and double the national rate of free school meal entitlement.

The school, which teaches about 100 pupils, has a long waiting list. Its volunteers use the synthetic phonic “Butterfly” method, devised by Irina Tyk, a headteacher and literacy expert. The study found an improvement of one month in reading age for every three hours 20 minutes of teaching. Children are taught how sounds are represented by letters and how to blend sounds to read words.

Among the successes has been a former pupil from Somalia about to start university and a 14-year-old girl writing a novel. Both return to help as volunteers.

A report last year by Ofsted, the schools inspectorate, said the best schools used “diligent, concentrated and systematic teaching of phonics”, but the demand for Butterfly’s services suggest this is not always being applied.

The study by the Educational Research Trust, a charity, used national databases to compare the results of pupils who attended the classes between 2002 and 2004 with those of children from similar backgrounds on the waiting list for the classes.

Katie Ivens, education director of Real Action, the literacy charity that runs the school, said its system could produce highly educated children from the most disadvantaged areas of the UK.

Article by Liz Lightfoot, published in The Sunday Times on 2 September 2012