The testing regime in England was criticised by a panel of key education figures this week, including the General Teaching Council's chief executive.
Keith Bartley told a gathering in Winchester of 100 of Britain's best teachers that what they could teach was being relentlessly controlled.
"We wonder why we have disaffected young people at the age of 14 or 15 when we have put them through a battery of 70 tests by that age," he said.
"Tests only test a very limited range of knowledge, much of which they have forgotten six weeks after they've taken the test, because the purpose of learning it was to get over a hurdle rather than expand their knowledge.
"The Government has a very centrist, determining tendency and it manifests itself in England more than any other country in the world in our testing regime."
Mr Bartley was speaking at a conference for past winners of the national Teaching Awards, marking its tenth anniversary this year.
Baroness Shirley Williams, a Labour education secretary in the 1970s, said there was too much intrusion and regulation. "The endless steeplechase of tests has got beyond reasonable," she said.
Lord Puttnam, the film director and Labour peer who founded the awards, said the consistent policies that education required seemed incompatible with England's short-termist political system. "Successive governments have been utterly mesmerised by the reactive views of The Daily Mail," he said.
Sandi Toksvig, the Radio 4 broadcaster, criticised the competing agendas of test standards and Every Child Matters. "As a parent it seems incomprehensible," she said.
Teachers at the conference broadly agreed with past award winners such as Tracy Stone, headteacher of Rookery Primary School, in Hansworth, West Midlands, in calling for more space for creativity.
The Department for Children, Schools and Families said it did not accept there were too many tests. A spokesman said: "There are statutory tests at only three points in the first nine years of compulsory education. That is hardly 'an endless steeplechase'."
This year's teaching awards, in October, have attracted a record 8,400 nominations.