“Art attack”, “Dreams” and “Funky Friday”. No, not films or rap records, but the titles given to the cross-curricular themed sessions cropping up in many secondaries as “boring, old” geography and history vanish from timetables.

But traditional subjects are not actually disappearing; they are simply being repackaged to make them more engaging. And despite the “trendy” names, this is more than a superficial rebranding. It involves staff teaching outside their usual subjects, longer lessons lasting up to three hours, more team teaching, and a generally more pupil-centred approach.

At the heart of this approach is the Royal Society for the encouragement of Arts, Manufactures and Commerce (RSA). Its Opening Minds curriculum, launched in 1999, is based on the idea that children today have to cope with a rising volume of information in a changing world. Pupils, it argues, face “a range of environmental, technical, social and economic challenges which go far beyond the scope of the national curriculum”.

The organisation concludes: “A curriculum which focuses only on subject content cannot provide students with the skills and abilities that they will need if they are to make a success of their future lives.”

Opening Minds involves re-organising teaching so pupils can acquire these skills. The idea is that while following the national curriculum, they also develop five key “competences”: learning how to learn; how to become active citizens; how to relate to others; how to manage situations; and how to manage information.

It involves teaching through practical experience as well as instruction, and a dissolution of traditional subject boundaries. It is very different, and catching on fast.

In 2003, just eight schools were piloting Opening Minds. Now, that number has rocketed to 204, and the society predicts it will shoot up even further as schools adapt to the emphasis on skills in the new secondary national curriculum.

Evidence also suggests the approach works. In a report published today, the RSA reveals that 93 per cent of the comments made about Opening Minds in school Ofsted reports have been positive; and 74 per cent of Opening Minds schools for which data was available had had their curriculum rated “good” or “outstanding” by Ofsted.

But a good Ofsted verdict does not necessarily mean all is well, as was shown by two cases highlighted in The TES earlier this month. Chafford Hundred Campus in Grays and Bishops Park College in Clacton-on-Sea both had Opening Minds-style curriculums praised by Ofsted last year. But both Essex schools received highly critical overall reports, with inspectors warning that some teachers lacked the skills needed to put the thematic lessons into practice. In fact, both schools ended up having to pull some subjects out of the themed approach.

So introducing Opening Minds is not easy. For teachers used to preparing and teaching lessons alone, it may mean working closely with colleagues and teaching in front of a peer for the first time.

They are also likely to be teaching subject material they have not been trained in - possibly in front of a larger group than normal, and for much longer sessions.

Some teachers have described the prospect as “very scary”; others like “stepping off a cliff edge and seeing if you can fly”.

Lesley James, the RSA’s head of education, recommends schools prepare for at least a year before they introduce Opening Minds.

“It takes a lot of planning and it takes good classroom management and structure,” she said. “These things are important anyway, but they are very important when you are introducing any innovation.”

But if teachers can manage the culture change, there are big rewards for an approach that is designed to engage pupils more in their learning. One said: “I feel for the first time I am teaching children - not just French.”

An RSA survey of schools using Opening Minds found that most said it had helped them make “good progress” in a range of areas, including behaviour, pupil self-esteem, creative teaching and social cohesion.

Yet the thematic, skills-based approach still leaves many uneasy.

Last year, Madeleine Cotson, head of Bowring Community Sports College in Knowsley, Merseyside, which uses a version of Opening Minds, told The TES: “You no longer need to go to school to get knowledge. You can sit on Google and find out anything you want at the press of a button.

“But what you do need to know is how to analyse that, how to interpret it, where to go for further information. You need to spend less time teaching the knowledge, but more time teaching pupils where they can find it out.”

These remarks are guaranteed to worry traditionalists who fear that subject content will suffer under themed teaching. Indeed, anyone with a realistic idea of what happens once pupils enter adult life might be concerned by her words.

Even if you set aside the fact that much of the “knowledge” on the internet is likely to be unreliable, a huge flaw remains in this argument.

It assumes that once you leave school, you will have the time to acquire all the knowledge you need. But the reality is that once the pressures of work and family set in, you almost certainly will not. In practice, the only time in our lives when most of us have the opportunity to acquire a large body of knowledge is in full-time education.

The idea that we can acquire knowledge later on, when it suits us, is nothing new - public libraries have been around for decades. But their existence has never persuaded people that schools should spend less time imparting knowledge. So why should the internet do the same now?

Mrs Cotson is not the only themed teaching enthusiast to argue that subject content is less important in “today’s fast-changing world”. But that does not mean subject knowledge has to suffer.

Ms James says it can all still be covered under the Opening Minds curriculum - just in a different way.

“Pupils might fall slightly behind in terms of subject knowledge during Year 7, but by the end of Year 8 they are ahead because they have become better learners,” she said.

Support and back-up is vital if schools are to achieve this. Bishops Park College shared the RSA’s views on the curriculum, but opted to develop its own approach. The school ended up in special measures, with Ofsted warning that its teachers sometimes lacked the subject knowledge needed for its thematic lessons.

Nick Pavitt, who became executive head of the Clacton school after the report, said: “This school chose not to use the Opening Minds project. Had it done so, it might not be in the position it is in now. It was trying to re-invent the wheel.”

Schools that do opt for the innovative new approach have a valuable new resource: the RSA Academy, which opened in Tipton in the West Midlands this term and has been set up as an Opening Minds centre of excellence. At the academy, all subjects are taught through two three-hour themed sessions each day. Teachers from other schools will be able visit and see how it is done.

But Ms James believes the key to success is for schools to take it at their own pace, much more gradually if necessary.

“You have got to look at your staff and think about what capacity there is to introduce a significant change to teaching and learning,” she said. “Every school is different.”