The recent performance tables on university entry subjects ignored the International Baccalaureate (IB) Diploma Programme and Pre-U, two existing alternatives to A levels. It's not unusual in this country for the focus to be narrowly on the nation's qualifications.

Intermittent government interference, meanwhile, is supposedly improving A levels: it has brought in an A* grade, and now plans to turn the clock back –A levels without modules again and, to the consternation of Cambridge admissions tutors, no more AS levels in their present form. The backtracking of one all-IB school to reintroduce A levels has been the talk of the town in some circles, while at the same time the Government can't get enough of its own so-called Baccs.

Rumours of the IB's death have been much exaggerated, to paraphrase Mark Twain. The IB silently thrives and continues to move from strength to strength, educating 5,000 students in 194 UK schools, most of which are state schools. The UK is in fact the third largest user of the IB worldwide, and the IB's reach continues to consolidate, as it has now established three new global centres in Singapore, The Hague and Washington, giving round-the-clock service for schools across hemispheres and time zones.

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The IB Diploma is a timeless classic, an icon of educational sense and high standards in a world where educational fashion shifts like hemlines, and much-needed clarity of thinking is elusive. The IB has never been more necessary. First, it believes in knowledge, and enables students to acquire it. It believes in the autonomy of subjects and academic disciplines, but also in their connectivity. It is global in its outlook, truly an education sans frontières. And it is grounded in fundamental values about culture and character. Visionary and inspiring, the IB can liberate and motivate the teacher and student. Practical, instructive and aspirational, it is the best possible preparation for university, for the workplace, and more importantly, for life.

Why do I believe this so strongly? The IB develops students that top universities want: students with expert subject knowledge; with the skills good students require – research, essay writing, footnoting; but above all, with the spirit of intellectual inquiry and critical thinking, the ability to challenge, argue and ask questions. Universities are clearly aware of this: the offer rate and acceptance rate for IB Diploma students is notably above other post-16 qualifications, including A levels, with an 87 per cent acceptance rate for UK-domiciled IB Diploma students last year. And in the US, the IB Diploma is a sought-after passport to top universities from Stanford to Yale.

The IB develops the future leaders the workplace needs – people who know how to collaborate and who know the value of teamwork, people with analytical ability, versatility, international understanding. The IB develops what a global society and a local community can't survive without – individuals who want to make a difference, who have developed the compassion and sense of public duty to contribute.

How does the IB do this? By a mixture of the compulsory and the optional; the IB offers a combination of testing assignments. In addition to traditional written exams at the end of the two-year programme, students analyse world literature (not just their national literature), focus on world events, create mathematical models to investigate them, and show practical skill in the laboratory. An IB student is required to continue studying in all areas of the curriculum at either Higher or Standard Level. All study at least one language, their native literature, maths, the individual and society and at least one science. Within the six subject groups the choice is wide, from French to Japanese, from biology to computer science, from medieval history to ecosystems and the environment.

The IB is assessed in varied and creative ways, including good old-fashioned terminal exams, proper essays, graphical calculator tasks, and the Group 4 Science project, in which students collaborate on a presentation of a broad scientific topic such as "Environment" or "Colour", drawing on their knowledge across all four science subjects offered within the IB – physics, chemistry, biology, technology and sports health and exercise science. This year students are investigating "Water" and our students will be collaborating with students from around the world through email, Skype and other real-time communication technology to collect and analyse local water samples, explore local environmental issues and present comparative analyses.

But what makes the IB more than the sum of its parts are the three core elements – the Extended Essay, Theory of Knowledge and CAS (Creativity, Action, Service). The extended essay is a 4,000-word piece of original research, tackling a specific question devised by the student and supported by a supervisor. Recent research includes the impact of invasive species on sub-Saharan food crops, or to what extent our brains can compensate for hearing loss. Other exam systems have imitated this, but the IB's original model leads to truly outstanding pieces of work – some at Sevenoaks have led to publication or patents!

Theory of Knowledge remains unique to the IB. More than its imitator – so-called "critical thinking" – "ToK" requires students to think across their subjects, to connect them, and to take one step back from their own perspective. It requires students to unpick their own assumptions, to think with clarity about real and challenging questions, such as the extent to which disagreement sparks knowledge, or how economic and social circumstances prime us to think in certain ways about the world.

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And then there is CAS – Creativity, Action, Service – which carries no points but gives students a structured opportunity to allow and reflect upon the flourishing of mind, body and spirit.

The impact of the IB on a school is liberating and motivating. It fosters a shared purpose and common ethos; it brings students and institutions around the world in touch; it validates the belief that there is no limit to intellectual endeavour. Our students prove this daily – they are getting into the world's top universities, are moving onto employment with relative ease – to the delight of their parents. Employers worldwide know that IB students know a lot, and more, can do things.

It's not just about becoming bankers and accountants. At Sevenoaks we are educating more medics than ever, teaching aspiring diplomats and environmentalists, musicians, artists, and, who knows, perhaps one day an IB Diploma Programme graduate Minister for Education might have some good and workable ideas that will actually help educate our nation.

Bacc to school: the rise of the International Baccalaureate

The International Baccalaureate (IB) probably received its biggest boost in the UK when Tony Blair used the 10th anniversary of his famous "education, education, education" pledge to say he wanted to encourage more state schools to take it up.

He said he wanted every local education authority to have at least one school or college offering the IB. At that time, it was on offer in only 43 state schools in the country. Last August, 122 out of the 200 schools offering the programme were state schools.

Tony Blair's enthusiasm in his speech for the IB was never quite matched by action on the ground – and the present Coalition Government is using all its energies up in improving the current UK examination system by returning A-levels to their traditional format of an end-of-course examination with more searching and open-ended questions than in previous years.

The Education Secretary Michael Gove's demand for more rigour in A-levels has at least made one school, King's College, Wimbledon, perform a U-turn over its decision to abandon them in favour of the IB. The two qualifications will now both be offered by the school.

Nevertheless, those state schools which do offer the IB speak favourably of its impact on pupils. Hockerill Anglo-European College in Bishop's Stortford, Hertfordshire, gets 60 per cent of its pupils into elite universities. George Green's School on the Isle of Dogs – which serves a much more disadvantaged catchment area – also believes it serves many of its pupils better than A-levels. "A-levels weren't doing it for our kids and didn't prepare them well for universities," head teacher Kenny Frederick said. "We wanted something that was a bit broader."

Increasingly, as controversy rages about Mr Gove's exam reforms – and speculation that they may not survive a change of government – heads are saying they may opt for an alternative to escape the political interference with the examination system.

Richard Garner