Pressure from right-wingers for a competitive market between schools has produced a sea of clear blue water between the Conservatives and its political rivals.

The extent of the changes in the organisation of schools being contemplated by the Conservatives emerged this week in briefing papers produced by the Number Ten policy unit. The Right wing of the party is keen to ensure that a further term of Conservative government would finally put an end to the comprehensive sytem.

The party has adopted ideas promoted by the Social Market Foundation think-tank to give all schools the independence to employ their staff and, within certain limits, to decide which pupils they will take. The Conservatives are proposing to create an internal market in education on the lines of the reforms in the health service.

In place of comprehensives, they want a range of schools offering varying degrees of selection and specialisms. Under their proposals, schools that failed to offer parents what they wanted would be closed and popular schools would be able to expand.

According to the theory, standards would be maintained by requiring schools to set targets, regular inspection by the Office for Standards in Education and a requirement for local authorities to carry out regulatory functions.

The promotion of greater academic selection would have to be regulated if all children are to find a place and the Conservatives are proposing that schools would have to apply directly to the Department for Education and Employment to became grammars. Grant-maintained schools will be able to select up to half their pupils without any reference to central Government.

The policy shift to the right in the Conservative party leaves Labour as the defender of comprehensive education. A future Labour government would have to deal with a system that already allows a degree of selection by ability or aptitude. The party would not give the go-ahead to any more grammars, but it is unlikely to take action against any of the existing 161 without evidence of substantial support for abolition from local parents.

Labour is hesistant about how far it would restrict selection in schools. The party is in favour of specialist schools and is expected to allow schools to select up to 10 per cent of intake on the grounds of aptitude for music and other specialisms. There are to be differences in the structure of schools with the creation of community, foundation and aided schools. Both aided and foundation schools will have control of admission policies, subject to agreement with their local authorities.

The defining difference between Labour and Conservative administrations is likely to be the switch in priorities from policies that confer advantage to middle-class parents able to manipulate complicated admissions systems that allow them access to the higher performing schools.

Labour intends to discriminate in favour of disadvantaged areas. The party has plans for education action areas, though restrictions on spending may limit its ambitions.There are, however, costed plans for homework centres that would provide places of study for those from less well-off backgrounds.

Labour appears to have taken to heart advice from education professionals on the need to concentrate greater effort on primary and nursery education. The party intends to focus on levering up standards of reading and numeracy in primary schools and, as a token of its good faith, has pledged to make a start on reducing the size of infant classes after its first year in office.

Labour also intends to scrap nursery vouchers - parents will stop receiving them by September - but it intends to provide nursery education for all four-year-olds. In the longer term, Labour wants to extend its plans for centres that combine day care and nursery education in a way that serves better the requirements of families where both parents work.

For reasons of its history, Labour has been forced to damp down expectations that there will be higher spending on education; hence the promise to abide by Conservative spending limits set for the next two years.

There is a certain justice in the Conservative claim that Labour has had a late conversion to measures it has put in place to raise standards. Labour intends to retain the national curriculum and regular testing. It has not signed up to the publication of league tables for results at seven and 14, but Labour will publish the tables of GCSE results and will require local authorities to publish the results of tests taken in the last year of primary school.

However, Labour promises to take a tough line on failure - closing down schools that are found to be below acceptable standards and allowing well-managed schools to take over any poorly performing neighbours.

The parties are offering the voters a clear choice. The Conservatives are intent on extending choice in a way that will benefit most those parents competent to play the system. Labour will retain a system where local authorities can impose limits on the extent to which schools can select children and intervene directly where there are problems.

The Liberal Democrats would take an even tougher line against selection and spend more money on the system.

* Gurus behind the policies, page 8

* Leaders, page 22