History lessons are "disappearing" in schools to be replaced by the teaching of "generic skills" because heads do not think it is a worthwhile subject, according to specialists.
Some children only get one year of history taught by a specialist, while others are banned from taking exams in case they damage the school's league table position, the Historical Association has found.
New Education Secretary Michael Gove has flagged up the importance of the subject. But a Historical Association survey of 600 teachers shows that a quarter of academies now merge history with other subject to teach generic skills. A growing number of comprehensives and grammar schools are following suit.
Twice as many schools as in 2009 are now running a two-year key stage 3 curriculum, which leaves less room for history on the timetable. This has risen from 5 per cent in 2009 to 10 per cent this year.
One comprehensive teacher told researchers: "We are disappearing. Integrated humanities is the way our senior management team wants to go and sees us as awkward, backward and obstacles if we suggest subjects like history are valuable in their own right. We constantly have to justify our existence".
Another said: "The history department is feeling that we shall disappear into a mix of 'thinking skills' and 'vocational pathways' which do not seem to recognise the contribution that history can make to developing young learners."
History at Year 9 is now optional in almost 9 per cent of comprehensive schools that took part in the survey, and in 23 per cent of academies.
In 2009, 72 per cent of comprehensives had history as a discrete subject in Year 7, by 2010 this fell to 69 per cent. Just 45 per cent of academies ran separate history lessons for their 11 and 12-year-olds.
Rebecca Sullivan, chief executive of the Historical Association, said the "squeeze on time" "is just one of many attacks".
"Ministers talk about its importance and yet we see a completely different story in our schools - the rate of increase for limiting specialist teachers is particularly concerning," she said.
The report's author, Richard Harris, a lecturer in history education at Southampton University and chair of the Historical Association's committee for secondary education, said some children were getting 38 hours of teaching a year while others in schools in more affluent areas had 200 hours.
"I'm concerned at the growth of this two-tier system," he said. "If you have less specialist teaching, children pick up less enthusiasm from the teacher.
"The Government must make a decision about what children are entitled to; we think this should be at least three years of history teaching by a specialist."
45% - Academies surveyed with separate history lessons for 11 and 12-year-olds
Surveyed teachers said students at their school were encouraged to take vocational courses rather than history because they were worth more on league tables.
About 16 per cent reported some kind of "restriction" on children's subject choices, making history out of bounds for lower achievers. This rose to 27 per cent among academies.
A third of teachers thought offering diplomas had a negative impact on GCSE history.
Most independents and grammars, and nearly three-quarters of comprehensives, have more than an hour a week of history teaching, against half of academies.