Analysis By Nick Assinder Political correspondent, BBC News website

Almost a week since David Cameron, either by accident or design, sparked a row over schools policy within his party there is no sign of it dying down.

Mr Cameron is accused of dumping core belief

As the row goes on the Conservative leader has upped the ante, with each day bringing new attacks on grammar school supporters - up to and including calling them "delusional".

He has now ratcheted the whole issue up again by saying the debate is so important that it will decide whether or not the Conservative Party is fit for government.

Mr Cameron insists he has not deliberately provoked this row in order to show voters that his party has changed - in the way Tony Blair did with his scrapping of Labour's historic Clause Four commitment to state ownership.

Aides claim he was taken by surprise at the furore which followed what they say was only a re-statement of a policy he had outlined many times before.

Lump it

The difference now seems to be the fact that the previously announced policy simply said there would be no more grammar schools or a return to a national eleven plus exam.

This time Mr Cameron, it is being argued, has gone further by rejecting the idea that selection by academic ability helps bright children escape deprived backgrounds.

Probably most in the Conservative Party had long resigned themselves to the fact there would be no more grammar schools or a return to selection at age 11. They perhaps did not like it but were ready to lump it.

Gordon Brown is presenting himself as new face

But to many, and they range across the party spectrum, to spell out a new policy explicitly rejecting selection as an aide to social mobility is going too far.

Mr Cameron points out that there were no new grammars during the 18 years of the last Tory government, says there will very likely be none in the future and even if there were new ones they would not survive a future change of government.

Mr Cameron, who unlike his grammar school educated predecessor went to public school, says the whole debate is a waste of time when the party should be, to borrow Tony Blair's words, concentrating on the many not the few.

In practical terms this means getting engaged in extending Labour's city academy approach, with more streaming and setting by ability within them.

And aside from the principles involved, he says crude politics mean parents' dislike of the eleven plus would make a commitment to grammar schools an "electoral albatross" for the Conservatives.

Eton

Partly it is the timing of this row which is important. It may be an attempt to grab the initiative on education and paint the Tories as "new" when compared with Gordon Brown.

He clearly believes his policy will find far more favour with the wider electorate he is attempting to appeal to than it does with Tory grassroots members.

It is still unclear how this will play out. If there is a real rebellion with resignations it may suggest the Tories are divided and still not ready to govern - a suggestion Gordon Brown has already made.

On the other hand, the whole episode may underpin Mr Cameron's leadership, find favour with the electorate and mark another significant split with the past.