Ministers' plans to allow more grammar schools to open are facing fresh opposition after a group of headteachers joined together to raise their concerns at the proposed expansion.
Secondary school leaders across Surrey have signed an open letter to Prime Minister Theresa May and Education Secretary Justine Greening to voice their "deeply held, vehement opposition to the Government's proposals to create a selective, segregated, two-tier state-funded system of education."
They are the latest group to oppose the expansion, which includes high-profile critics such as Ofsted chief Sir Michael Wilshaw.
Announcing plans to allow grammar school expansion in September, the Prime Minister said selective schools can help the life chances of poor pupils, and argued that under the current system there is ''selection by stealth'' based on parents' wealth and ability to buy houses near the best schools.
In their letter, the 64 headteachers, who are represented by the Surrey Secondary Headteachers' Phase Council, said: "The comprehensive schools in Surrey have delivered in the past 40 years an education system which genuinely is for everyone, with able pupils achieving highly, social mobility and the absence of the stigma of failure at the age of 11.
"We can see students who are steady late developers, so who would probably have failed the 11-plus, and yet have gone on to be 'high-fliers'.
"It is impossible to have grammar schools without secondary modern schools or their equivalent for those who are not selected, whether by 11 plus or some other test.
Around 95% of pupils in Surrey attend secondary schools that are rated as good or outstanding by inspectors, the letter said. It is understood the county does not have any grammar schools.
It went on to say: "At its best, the Government's selective school proposals represent further confusion and fragmentation of England's education policy.
"At its worst, this policy is predicated on a nostalgic and unrealistic vision of society, the debate around which deflects attention from the real issues facing schools today: continuing funding cuts, an unassuaged and escalating recruitment crisis and the introduction of new GCSE qualifications with yet-to-be defined grade boundaries and, in many cases, ill-prepared specifications, to name but a few."
A Department for Education spokeswoman said: "The Government wants to make this a country that works for everyone, not just the privileged few.
"Grammar schools have a track record of closing the attainment gap between children on free school meals and their better off classmates, and 99% of grammar schools are rated good or outstanding.
"We want all children, whatever their background, to have access to an education that will unlock their talents. That's why we will scrap the ban on new grammar schools and make more good school places available, to more parents, in more parts of the country."