Lord Hattersley assumed the mantle at the SEA's annual conference with a withering attack on the Government's specialist schools programme and its "covert selection".
The Government, unperturbed, yesterday announced another 79 specialist schools.
The association, riven by internal politics which have seen many of its more moderate members drift away, has become increasingly detached from the Labour Party - although it still proclaims arch New Labour moderniser Steve Byers among its vice-presidents. And Education Secretary Estelle Morris is still on the membership list.
Set up in the early 1920s, for decades it served as the party's education think-tank. It now considers its role to be a "critical friend" to the Government. Its long-standing priority has been to end selective education - a cause passionately followed by Lord Hattersley.
He attacked the Government for reintroducing "selection by stealth" and denigrating comprehensive schools as "bog-standard". That comment, by the Prime Minister's spokesman Alastair Campbell, typified the worst of the campaign against comprehenives and was "crude, ignorant, prejudiced".
Specialist schools created a hierarchy, he said, attracting the "more articulate, self-confident and motivated parents". Other schools would deteriorate.
"Selection always divides students according to class. It will be the same with the Government's covert selection as with the more honest kind."
The Department for Education and Skills yesterday named another 425 beacon schools - now totalling 1,000 - and a further 79 specialist schools, bringing the total to 684. Both have hit their targets early. Tony Blair has set a new target of 1,500 specialist schools by the next election.
The new batch includes 33 new technology colleges, 18 language schools, 16 sports colleges and 12 specialist arts schools. Half are in Excellence in Cities areas.
A spokeswoman for the DFES said the message was "diversity". "These schools are developing their own culture, character and ethos. They have their own identity and they're building on it by working with other schools."
The announcement was accompanied by a new study of beacon schools by the independent National Foundation for Educational Research. It found benefits to staff both in beacons and in their partner schools, with better practice and improved pupil and teacher morale.