I was disappointed that the debate on ability-group teaching (5 April) did not discuss why successive governments have supported teaching in ability groups.

A member of the present government has pointed out that only one vote in 60 affects the outcome of a general election - and this one in 60 voters tends to be middle class, middle ground. This means that governments make the political judgement that the “parents who matter” are the sort that don’t want to see their middle-class child in the same group as some low-ability, working-class child who might, after all, have some behaviour problem. The clear solution in this case is for these low-ability students to be separated out - meaning that their education is considered as being less important than political success.

So despite past research that tends to suggest that mixed-ability grouping is generally more successful than grouping by ability, we are given the impression that setting beats all. Also, since the national curriculum expects teaching in ability groups, it is easy for inspectors to criticise schools teaching mixed ability because they are not conforming to government policy.

Mike Rath, Exeter.