Some 18.5 per cent of children in English primary schools are eligible for free meals – the government’s standard measure of deprivation – compared with 17.1 per cent a year earlier.
In secondary schools, 15.4 per cent of pupils can claim free lunches this year, up from 14.5 per cent in 2009.
Pilots of universal free school meals for primary children were introduced in three local authorities last September, which would account for a proportion of this rise.
Christine Blower, general secretary of the National Union of Teachers, said: "The number of primary school pupils entitled to free meals has gone up in part because of the additional provision… which we thought was a very good idea.