This week I have written to Ed Miliband, calling on him to guarantee the status of England's existing 164 grammar schools in the event he becomes Prime Minister.
Why? Because a new poll conducted by ComRes has found four in ten (39 per cent) believe Labour will axe the remaining grammar schools if they win the election.
If they do, the Labour Party will be betraying thousands of bright pupils from poor backgrounds who will be the most damaged by such a move.
The poll finds half (51 per cent) of the British public support the opening of new grammar schools, while just one in ten (10 per cent) oppose them.
One half (48 per cent) think grammar schools give less privileged young people a chance to succeed, while fewer than one in five (18 per cent) think they are bad for social mobility.
And in an additional blow to those who claim grammar schools only help those who are privileged already, one half (46 per cent) of working class respondents think grammars are good for social mobility while only one in ten (10 per cent) do not.
Where there are grammar schools in the United Kingdom, social mobility is booming. At the upcoming general election, there is a huge political opportunity for any party that chooses to champion social mobility by actively supporting and promoting grammar schools. Unfortunately neither the Conservatives of Labour have done this, despite today's overwhelming evidence.
More than half (52 per cent) believe the ban on opening new grammar schools in areas that do not have any harms parental choice. 58 per cent think selective schools help to drive up educational standards.
Twice as many British adults say they are more likely to vote for a party that promises to bring back grammar schools than say they are less likely to do so (20 per cent and 10 per cent respectively).
Three in ten (29 per cent) supporters of Ukip, the only party which supports more grammar schools, would be more likely to vote for another party if that party pledged to bring back grammars.
The Tory leadership has dithered and delayed for too long over plans for a new grammar school annex in Sevenoaks, Kent. And now, ten days from polling day, fears are growing that Labour may seek to close the remaining selective schools altogether if it wins the keys to Number 10.
I'm calling on Ed Miliband to give us his personal assurance he will do nothing to undermine these fantastic grammars - and that they won't be closed under any government led by him.