For instance, in 2006, pupils in England's 164 grammar schools produced more than half the total number of A-grade A-levels in "harder" subjects than those produced by pupils in up to 2,000 comprehensive schools, according to the National Grammar Schools Association.
This was "unfounded" because there is a diverse school share, from free schools sponsored by universities to faith schools.
He said: "This will be a hugely significant day for selective education in the country".
Schools Week searched the consultation document for the terms special education needs, special schools and SEND - but these terms were not included in the publication. "I'm struggling to believe it on the basis this evidence".
Formally unveiling the flagship reform in the Commons, Education Secretary Justine Greening claimed it would boost choice and social mobility.
But May insisted there would be no return to the "binary" system of grammars and secondary moderns of old, even though children would still either pass or fail exams to enter selective schools at age 11 and upwards. "I strongly oppose 100% faith schools and will be voting against religious segregation of our children".
"It is a future in which every child should have access to a good school place".
Mr Ireson said ministers had to "think about those children who aren't going to the grammar school" and what they would need.
And Greening went on, but effectively failed to give any firm proof that grammar schools would help to deliver a quality education for all of the UK's children.
She added: "In a true meritocracy, we should not be apologetic about stretching the most academically able to the very highest standards of excellence".
May rejected the criticism, saying she wanted to increase schooling options in a policy that taps into a rich vein of traditional conservatism in the suburbs and rural communities in so-called "middle England", a key electorate for the new leader.
As we reported, the policy has been introduced by the King Edward VI Foundation, which runs five grammar schools in Birmingham - King Edward VI Aston, King Edward VI Handsworth Girls, King Edward VI Camp Hill Boys, King Edward VI Camp Hill Girls and King Edward VI Five Ways.
But shadow education secretary Angela Rayner said that while Labour had promised "education, education, education" the Conservative government's policy amounts to "segregation, segregation, segregation".
Ofsted's chief inspector of schools, Sir Michael Wilshaw, said the idea that poor children would benefit from a return of grammar schools was "tosh" and "nonsense".
"They could, as a condition, be asked to establish a good new non-selective school or open a good feeder school, or might partner a non-selective school and sponsor it to allow pupils to attend certain subjects".
When Justine Greening gave her statement in the Commons this afternoon, she repeated numerous Prime Minister's own lines about selection already existing through house prices and so on.
"By enshrining selection into our education system the Prime Minister is wilfully ignoring the overwhelming evidence that selection at 11 leads to a more unequal country".
Labour's John Asworth said it was "utterly ludicruous" for the PM 'to stand up and talk about creating a great meritocracy and then in the next breath announce a return to grammar schools'.
Lincolnshire NUT Divisional Secretary Ken Rustidge said that he was concerned about how the proposals would impact on non-grammar schools in the county.