Among measures being considered for the Conservative manifesto is a plan to compel all secondary schools to opt out of local authority control. The commitment to an expansion of the grant-maintained sector was underlined last week in a Times interview given by the Prime Minister in which he looked forward to the day when all state schools were self-governing.

Gillian Shephard, the Education Secretary, under pressure this week to explain what the Prime Minister had in mind, revealed that initiatives to increase the number of grant-maintained schools were “manifesto territory”.

She said work was being done on the ways in which the benefits of opting out could be extended to all schools. Questioned later on the BBC’s World at One, she refused to say whether she was in favour of schools being compelled to opt out.

The apparent difference in view between her and John Major was seized on by Labour as evidence of confusion over education policy. David Blunkett, the party’s education spokesman, said Mrs Shephard was embarrassed by Mr Major’s backward-looking agenda.

However, Labour’s own internal divisions on the future of grant-maintained schools could be exploited by the Conservatives during an election campaign. The latest policy statement which envisages the survival of grant-maintained schools as foundation schools has angered activists.

The problem for both parties is that opinion poll evidence suggests parents are more concerned with exam results than with whether schools are run by local authorities or funded from Westminster.