The Association of Teachers and Lecturers is calling for the national curriculum to be scrapped in favour of a locally determined curriculum that would focus on skills, not knowledge. Its proposed system would put emphasis on physical, creative and interpersonal skills as well as the academic.
The union, which holds its annual conference next week in Bournemouth, will detail its ideas in a book entitled Subject to Change.
Mary Bousted, ATL general secretary, said the proposals aimed to re-engage pupils alienated by tests.
"Ever more we are driving young people down a route where even the academic ones are dispirited and demotivated," she said.
"Why are we the poor man of Europe in terms of people leaving school at 16? Our system is over-assessed and over-packaged. Pupils need to be given the skills to be enquiring."
Martin Johnson, acting ATL deputy general secretary, said schools should decide the curriculum according to local circumstances and examine topics ranging from how to use tools to "walking in a variety of different styles, according to purpose".
He said it was ridiculous that, in the age of the internet, pupils across the country were learning the same things. "For the state to suggest that some knowledge should be privileged over other knowledge in a 21st century environment is a bit totalitarian," he said.
The proposals will be among the talking points at the conference. Another topic under discussion will be teachers' health and safety at work, with delegates calling for the installation of sprinklers in all school buildings.
There will also be a call for the rapid removal of all asbestos from school buildings. The debate follows news this week that Margaret Worthington, 69, a retired teacher from the West Midlands, contracted cancer from asbestos threads in school pinboards.
The conference will examine the effects that technology such as computers and mobile phones have had on children.
Ralph Surman, a national executive member, said: "They play computer games all night and come to school tired out, send hateful texts and emails and download porn from the net."
Other conference motions will focus on cyber-bulling of teachers, pay for higher level teaching assistants, the work-life balance of newly-qualified teachers and sustainable schools.