A frontbench Conservative MP has been "severely reprimanded" by the party's chief whip after suggesting selective schools can boost overall standards.
Mr Brady is a former grammar school pupil himself
Graham Brady was told to stick to his brief as Europe spokesman.
The Altrincham and Sale West MP spoke out in defence of grammar schools in the row caused by the party's decision to turn against selection by ability.
He released data to the Times, suggesting areas with selective schools got better exam results.
Party leader David Cameron has promised more city academies - the privately sponsored state schools championed by Prime Minister Tony Blair - and more streaming and setting within existing schools.
But former grammar school pupil Mr Brady supplied data to the Times which indicated that in areas with no selective education fewer pupils get five or more GCSEs at grade A*-C including English and maths.
"These facts appear to confirm my own experiences: that selection raises the standards for everyone in both grammar and high schools in selective areas," he told the paper.
"It is vitally important that policy should be developed with a full understanding of all of these facts, which might lead to the introduction of selection in other ways."
Fellow Conservative Nigel Evans, MP for Ribble Valley, said Mr Brady should "absolutely not" be censured for speaking out.
He said the way that shadow education secretary David Willetts announced the policy "looked as if it was an attack on grammar schools".
"Graham would not have been doing his job if he had not stepped in and defended the grammar schools," Mr Evans told BBC Radio 4's Today programme.
"But at the same time Graham is 100% behind ensuring that the academies that David Willetts and David Cameron wish to see rolled around the country is going to become a reality so that youngsters of all abilities can get the education that they deserve."
Mr Evans said he himself would continue to speak out about the grammar school he attended and the one in his constituency, but was also going to support the party's policy.
"We are all getting behind the policy of ensuring that we're now going to concentrate and focus on those schools, those areas where youngsters are looking for a good education but at the moment it's not happening."
A number of newspapers cite Conservative Party sources as suggesting Mr Brady may be axed from his role in a party reshuffle expected this summer.