It is often derided as a government attempt to instil outmoded, quasi-patriotic values in young people, yet, less than seven years after it became a compulsory part of the curriculum, citizenship has become the fastest-growing GCSE subject. And this summer will see pupils sit the first full A-level in citizenship, boosting its credibility among other subjects.
David Kerr, of the National Foundation for Educational Research (NFER), says the speed of change has been remarkable: "In just a few years, this country has gone from being behind the game in citizenship to (being) one of its leading proponents."
In many European countries, pupils do not sit exams in citizenship. But in England, pupils have opted for the GCSE in droves, thumbing their noses at the subject's many detractors. Some 90,000 sat GCSE citizenship this year, more than double the number in 2005. More than 300,000 young people have sat the short GCSE since 2002, and a full GCSE is available from this year. In Scotland, citizenship will form one of the four "capacities" on which its Curriculum for Excellence is built, but there it is mostly delivered through cross-curricular work rather than as a separate subject.
About 400 pupils have opted for the AS-level, which has been available since 2008, with some sixth forms already abandoning general studies in favour of the citizenship AS.
At the other end of the education spectrum, Sir Jim Rose's recent review recommended that citizenship should be a requirement in primary schools. All this suggests it is not just a government-imposed fad, but a subject with real momentum.
The subject's popularity has coincided with a move towards more active citizenship in recent years. In most other countries, including the US, citizenship education is still wedded to the textbook. But a longitudinal study by the NFER found that use of textbooks in citizenship lessons in this country has been decreasing since 2002.
From the outset, this concept of active citizenship meant debates about topical political and justice issues, often using news reports and materials from charities and organisations such as Greenpeace and Oxfam. Increasingly, volunteering, campaigning and other community-based activities - with their significant out-of-school element - have set the subject apart.
"Pupils enjoy doing things rather than being talked to," says Heather Siebenaller, a teacher at The Ridgeway School in Swindon and subject leader at the Specialist Schools and Academies Trust.
Nick Nielsen, director of the community-based activities charity Envision, says: "Active citizenship allows young people to take responsibility and see that it is rewarding to have responsibility. It doesn't matter whether it's labelled citizenship or anything else."
From modest beginnings in 2000, Envision has grown exponentially and now supports citizenship projects in more than 100 schools. "Youth involvement is the Zeitgeist at the moment," says Mr Nielsen.
In France and many Eastern European countries, citizenship education focuses on identity; bringing young people together in a sense of nationhood. Here in the UK, the main concern was youth apathy and how to encourage participation.
"It was decided we could not force a sense of Britishness that did not exist," says Jeremy Hayward, lecturer in citizenship at the Institute of Education in London.
Now citizenship pupils are writing to local councillors, campaigning against knife crime, and even recently demonstrating against a new runway at Heathrow airport.
"Most MPs will tell you their mailbags are bulging, often because of a citizenship class," says Mr Hayward.
Ben Hammond, London adviser for the Association for Citizenship Teaching, says schools are becoming more confident about the activities in which they involve pupils.
"They are beginning to realise that it is perfectly possible to give children an experience of taking action and that it is a legitimate way to learn," he says. "The new curriculum is not bound by the classroom. The community informs the curriculum."
But despite this loose definition of active citizenship, teachers of the subject say they like the formal qualifications because it puts citizenship on a par with other academic subjects.
Tony Breslin, chief executive of the Citizenship Foundation, says: "It is right that there should be an option at A-level. If large numbers are doing citizenship GCSE, some will want to continue it."
New GCSE specifications mean that 60 per cent of the exam is coursework based on active involvement, up from 40 per cent.
But the academic rigours of A-level could see the very element that attracts pupils - the subject's practicality - toned down. Robin Kyne, director of learning at Regent College in Leicester, which trialled the AS-level, felt early versions of the exam were not active enough.
"For us, citizenship is about getting up and doing things in the community," he says. "The AS-level specification before was very dull, dry and academic, so we had to fight our corner in the beginning." This year, 350 Regent College students chose AS citizenship.
"The way we've run the AS-level there is still academic rigour, but students go out and complete an active project. The two sit together very well," says Mr Kyne. "Our desire would be to make the full A-level more active and more independent."
Exam boards may have made the AS-level more hands-on in response to feedback, but they are less likely to give way on the full A-level, for fear of diluting the "gold standard".
Tony Thorne, consultant to the Citizenship Foundation and author of a citizenship textbook, says: "I feel strongly that we should be measuring pupils' understanding of issues."
The balance of active and academic will continue to be thrashed out. But the debate is being seized upon by critics, who say citizenship is all things to all people rather than a discipline on a par with history or geography, or even a vocational subject that requires a specific set of skills.
"Citizenship is not an academic subject," says Frank Furedi, professor of sociology at the University of Kent. "Focusing on the active merely exposes the lack of content in citizenship. It takes people's experiences, which they might do anyway, and rebrands them as citizenship to endow them with value." In short, he says, it is "an affirmation of self" as much as anything else.
Other examination systems such as the international baccalaureate (IB) have always incorporated such "self-directed learning" in their non- examined but compulsory Creativity, Action, Service (CAS) module.
The goals of CAS and GCSE citizenship are very similar, says Mina Cullimore, head of RE and citizenship at Barton Court Grammar School in Kent, which teaches citizenship to GCSE but shifts to the IB in the sixth form. "Both centre on being involved in the community and contributing to community issues," she says.
But the International Baccalaureate Organisation believes CAS should not be graded. "It is about one's own development, a subjective and very personal exploration," Ms Cullimore explains.
Mr Breslin, too, sounds a note of caution about the exam route. "If we continue with subjects such as citizenship into sixth form and turn them into examination factories, we will take away the space for the natural development of citizenship," he says.
"GCSE and A-level can provide a very good anchorage point, but we must never subjugate this to citizenship learning through a broad range of practice."
But as the popularity of the subject grows, organising that active aspect for hundreds of pupils could become a logistical nightmare. Successful schools have many different opportunities for pupils to become involved. Mr Breslin describes around a third of secondaries as "citizenship- rich".
To an outsider, they look like schools with a huge range of extra- curricular activities open to all pupils - from student councils and youth parliaments, to environmental schemes, school linking projects and volunteering in the community. Their GCSE and A-level citizenship students can pick their projects from among these.
Mr Kyne says: "A quarter of our students are involved in volunteering, whether or not they do citizenship."
Mr Breslin refutes the criticism often levelled at citizenship - that it is simply an amalgam of the extra-curricular, character-forming activities that have been squeezed out of the curriculum in recent decades.
"Schools may be doing all the active stuff, but they may not be turning these activities into learning," he says. "They may be doing any number of sponsored walks, but there is no substantive curriculum that explores the issues and politics.
"If students aren't encouraged to understand that activism, volunteering and fundraising are community aspects of citizenship, then they are just doing good.
"We don't just talk about active citizenship, but effective citizenship. Effective citizenship is not just `busy' citizenship, but reflecting."
Whether this is what's actually happening in citizenship lessons is another matter. A recent NFER report found that youngsters remembered certain issues and activities, particularly if they were highly topical, but were hazy about citizenship as a subject.
Ofsted reported in 2005 that it was among the worst taught secondary level subjects, with pupils having little idea of what it was about. An update of that report will be released in September.
Meanwhile, the focus has been on bringing more specialist citizenship teachers into schools to tie activities to specific learning outcomes. About half of citizenship teachers are trained in the subject, with 200 citizenship PGCEs awarded each year.
"That means that 50 per cent have not (been trained in the subject), something that would not be acceptable in any other curriculum subject," says Mr Kerr.
Trainee citizenship teachers include people with a wealth of relevant experience, from human rights lawyers to former EU and UN officials and charity workers.
"Active citizenship does require an additional compliment to traditional teacher skills," says Mr Hammond. "It needs a knowledge of the community and an understanding of how to bring about change. Teachers can help pupils negotiate pitfalls and thinking outside the classroom."
It is difficult to predict whether a move to more active citizenship will change young people's attitudes. But teachers are already reporting some benefits.
Alison Fairclough, citizenship co-ordinator at Oldham Sixth Form College, describes citizenship as a "safety valve" against the racial tensions that have boiled over in the town in the past. "There is a knock-on effect. Students want to talk about things," she says.
Gillian Temple, Oxfam's head of education and youth, agrees that it is what pupils do with what they have learnt that endows the subject with its value.
"Once the bell goes and young people are out of the classroom, they can use what they have learnt," she concludes. "I think young people are becoming more active in a way we haven't seen for perhaps 40 years."