Politicians are better at passing laws than at heeding the law of unintended consequences. The abolition of grammar schools was supposed to increase social mobility. Instead it has done the reverse. Even Ruth Kelly, the Education Secretary, admitted recently that comprehensives had not been the engine of social mobility and equality that their architects had hoped. Indeed, as a recent LSE study for the Sutton Trust found, social mobility in Britain has actually worsened since grammar schools were phased out.

Hence the uproar in Northern Ireland over the Government’s plans to abolish academic selection in the Province. Northern Ireland still selects by 11-plus and the results have been startling. The percentage of pupils gaining five GSCEs at good grades is ten points higher than in England. At A Level, too, schoolchildren in Northern Ireland outperform their English counterparts: 30 per cent of subjects taken were awarded an A grade last year, compared with 22 per cent in England.

It is indisputable that bright children, particularly from lower-income families, benefit from a grammar-school education. Freed from the peer pressure that denigrates academic success — especially strong for boys — and educated alongside others of similar ability, they achieve results better than those they would have gained at an average comprehensive. Research by David Jesson, of York University, earlier this year found that those pupils who left primary school with the best grades did nearly twice as well in their GCSEs if they were taught with other very intelligent children than if they were the only very able child in their year group.

But what about those children who are not so academically gifted? Surely they should not be allowed to sink at a secondary modern? Oddly, their parents do not seem to agree. In two public consultations over the future of grammar schools, parents of 11-plus “failures” seem as keen on the system as those whose children are more able, though obviously those parents want comprehensives of the highest quality.

The only parental ballot so far undertaken on grammar schools, in Ripon, produced a two-thirds majority in favour of retaining the system. A similar household survey in Northern Ireland found 64 per cent support for maintaining academic selection there — which makes the Government’s action all the more disgraceful. Since the Ripon ballot, five years ago, the grammar school and the comprehensive have successfully collaborated, with none of the social divisions that opponents of selection might expect.

Tomorrow a member of the Professional Association of Teachers will call on his union to back a motion to bring back grammar schools. In the present climate, he has little hope of success. But it does seem absurd that a Government keen to improve the life chances of the poorest should be kicking away their ladder to success in the one part of the country in which social mobility is still relatively high.