By the age of 12, he was already a fearsome debater. “He was very much an individualist, and in that respect he stood out from the crowd,” says Mike Duncan, former head of English at Robert Gordon’s College in Aberdeen and also in charge of its debating team. “He was representing the school and winning debates from a very early age. He was clearly someone with great natural skill and aptitude.”

But whatever the inborn talents of Michael Gove, it was his school that nurtured and cultivated that verbal adroitness. It has a long-standing and active debating society where, Mr Duncan believes, pupils can hone their “skills to be articulate, think on their feet and argue in a positive manner”.

For him at least, it is no great surprise that his star pupil is now in charge of every state school in England. But the Education Secretary is hardly unusual in not being a product of the maintained sector, in which all but a tiny minority of children are schooled.

More than a third (37 per cent) of MPs elected in May were educated at private schools, which are attended by just 7 per cent of the school population, although this figure is increasing (see map on p22).

The current Parliament is the most socially elite for 13 years, but this is not only the result of a resurgence in the fortunes of the Conservative Party, a larger proportion of whose MPs have traditionally been educated outside the state system. While Tory gains explain some of the increase, in reality it is simply part of a growing trend across the political class as a whole.

After a long period of decline, the proportion of MPs who have been privately educated has been rising since 1997, Labour landslides notwithstanding. Among Labour MPs, the number who went to private school has been increasing since 1992, until it fell back this year. The past two elections have also seen a rise in the proportion of Lib Dem MPs who went to fee-paying schools.

The precise reasons why so many private school alumni are at the pinnacle of politics - and so many other professions - are complex. Certainly, family wealth, background, support and expectation all play their part, but the disproportionate number of privately educated MPs - when set against the wider population - suggests that school is a major factor in future success. So what is it that private schools do to produce so many future leaders? And is it something state schools can - or even should - emulate?

Freed from the constraints of admissions policies, private schools, along with grammars and selective state schools, are able to cherry-pick the most able pupils. These children are likely to enjoy a confidence in their own abilities from an early age.

Debating clubs, house and school prefects, the Combined Cadet Force (CCF), public speaking and being encouraged to take on teaching responsibilities with younger pupils all help to develop young people’s leadership abilities in a way that bodes well for future career success.

While state schools might like to offer extra-curricular activities, such as debating, there is a temptation to focus on more mundane activities that will help improve their performance in the league tables. Enhanced exam preparation may help to improve children’s grades, but not necessarily their ability to stand up and be heard in public.

Private school alumni can also call on the “old boys’ network”, a mysterious system of preferment and favours for those who are “one of us”.

A Mail on Sunday report in 2007 claimed that Prime Minister David Cameron’s break into politics, a job in the Conservative Party’s research department, came after a phone call of recommendation from a member of staff at Buckingham Palace.

Heads of private schools agree that their structure and ethos is designed to instil a sense of entitlement and self-assurance that gives pupils the opportunity to reach the top in whichever field of endeavour they choose.

Eton College is well known for its distinguished former pupils, among them 19 British prime ministers, including Mr Cameron.

There are 20 old Etonians in the current parliament: 19 Conservatives and one Lib Dem - five more than in 2005 and representing by far the highest proportion of alumni from any single school (see box).

Tony Little, headmaster of Eton College, recognises its powerful heritage but insists that self-belief comes from the pupils themselves rather than being imposed by others.

“I speak to all 260 school leavers and many tell me the same thing: that they expect excellence of each other,” Mr Little says. “That’s a pretty powerful thing, which creates a momentum of its own. When your peers set the bar, it can lead to quite a competitive but aspirational environment - a swathe of boys who want to make a positive difference in all fields, be it politics, the arts or business.”

All schools, whether private, state or grammar, profess to instil this “can do” attitude that allows pupils to aim high. Yet the opportunities available to children from privileged backgrounds continue to outstrip those on offer to youngsters from less fortunate families.

The best jobs in Britain still go to old boys from top private schools, according to a recent report from the Sutton Trust charity. It found that more than half of leading news journalists, medics and chief executives and 70 per cent of barristers and judges were educated at private schools. In politics, 13 schools (12 of them fee-paying) produced a tenth of all MPs in the new Parliament.

Reading School is the exception, proof that private schools do not have a total monopoly on power. Four of the selective state school’s former pupils are MPs, including the Conservatives Oliver Heald and Mark Field.

Mr Gove admits Britain has one of the most “stratified and segregated school systems in the developed world”. The gap in exam performance between private and state schools grew under Labour, he said during the recent Queen’s Speech debate.

One of the apparent advantages of private schools is their ability to get their pupils into Oxbridge. In the same debate, Mr Gove took delight in pointing out that more young people went on to Oxbridge last year from the private school attended by Harriet Harman, acting leader of the Opposition - St Paul’s in west London - than from the entire population of pupils eligible for free school meals.

Lee Elliot Major, research director of the Sutton Trust, believes worrying divisions are growing. MPs typically come from a small number of prestigious schools, which dominate admissions to elite universities, which in turn open doors to influential professional positions, he says.

For 2008-09, both Oxford and Cambridge had a Government target to accept just under 70 per cent of new full-time undergraduates from state schools. However, just 54.7 per cent of Oxford’s new undergraduates were state- school educated; at Cambridge, the proportion was 59.3 per cent.

“Oxford is like a mini-parliament,” Dr Elliot Major says. “It’s a training ground where young people can argue their case in front of a packed auditorium just as they would as politicians. Those who can afford to - such as David Cameron and (deputy PM) Nick Clegg - then go on to become researchers and advisers before becoming politicians themselves.”

When interviewing applicants, Oxbridge admissions tutors look for academic excellence and strong “life skills” - something the top private and state schools are adept at developing, Dr Elliot Major argues.

“A lot of state schools are driven by a league-table culture that isn’t necessarily the best for children in their later lives,” he says. “Internships are open to young people who are articulate, confident, self- sufficient and good at presenting themselves. You don’t learn those skills by solely going down the academic route - it is from debating, presenting, public speaking and stretching yourself. It is a real challenge for schools without many resources to offer those kinds of experiences.”

But Mr Duncan insists that state schools are just as capable of fostering talent as their private-sector counterparts. During the early 1980s, when Mr Gove was a pupil at Robert Gordon’s, a number of state schools enjoyed good reputations for debating. He argues that being in the maintained sector should not inhibit a school’s ability to provide good leadership or debating opportunities.

“It is more down to having the members of staff who are keen to sustain and develop debating,” Mr Duncan says. “Together with having pupils who have some sort of natural talent and enthusiasm, that is what really makes the difference.”

At schools such as Eton, “extraordinary opportunities” are in abundance, Mr Little says. A tutor and house system provides all 1,300 pupils with individual attention, while a 570-year-old tradition sees university academics introduce sixth-formers to subjects beyond the A-level syllabus - from Italian Baroque architecture to philosophy or ethics. The idea is to stretch intellectual curiosity, promote independent thinking and prepare pupils for leading universities such as Oxbridge.

The 70 or so societies at Eton cover interests from wine to politics and also instil pupils with leadership skills. The boys themselves are responsible for choosing, inviting and arranging visits from guest speakers. Harry Potter author J.K. Rowling, iconic fashion designer Dame Vivienne Westwood, veteran actor Sir Ian McKellen and the exiled King Constantine of Greece are among those who have accepted invitations to address Eton pupils.

But these leadership opportunities are not beyond state schools’ grasp. At King Edward VI School in Bury St Edmunds, in Suffolk, leadership is a priority. Pupil leaders introduce all assemblies; “sports leaders” work at King Edward’s local partner schools with younger pupils; sixth-form maths and literacy leaders work alongside teachers to develop pupils’ confidence in learning, while the school council makes “real decisions” on “real issues”, says headteacher Geoff Barton.

And there are more exotic options. A group of Years 9 and 10 pupils has recently returned from Shanghai, where they ran a week of leadership activities with Chinese pupils. Closer to home, the school chooses to take on private schools in sporting and debating matches - with considerable success.

“For me, it is about raising our own aspirations and showing that we are willing to compete at the highest level,” says Mr Barton. “It means that some of the old stereotypes of the state-versus-independent system are falling away because we are showing that, as a state school, our aspirations are second to none, and that our pupils deserve to have great opportunities, irrespective of their background or parents’ income.”

It may take some time for these efforts to produce more state-educated MPs - or other leaders in society - but it is a similar story at Haverstock School, a state school in Chalk Farm, north London, which reflects its diverse local community. Some of its pupils are from affluent backgrounds, but a quarter come from refugee families.

Among the school’s alumni are brothers Ed and David Miliband, both candidates for the Labour leadership. Oona King, the former MP who recently launched her bid to become Labour’s candidate for Mayor of London at the school, is another former pupil.

To encourage its current cohort to follow in their footsteps, the school concentrates on exposing young people to a world of work that hitherto may have appeared closed to them.

Its two career academies - one specialising in business and finance, the other in media - offers sixth formers access to top companies that provide pupils with mentoring, six-week paid internships and “guru lectures”.

Since the first academy was set up four years ago, headteacher John Dowd has noticed that many more pupils are aspiring to go on to higher education. Last year, every sixth former who took part in the finance academy went on to study a related subject at university.

“It gives the pupils direction in their lives,” Mr Dowd says. “They get the chance to work alongside Oxbridge graduates - it is a massively different environment to getting a part-time job at Sainsbury’s.”

From there, the pupils are encouraged to set their sights high. Armed with a broader outlook, plus a handful of useful contacts, Haverstock tells them that the world is their oyster.

“We want our pupils to feel that it is good to come from an inner-city background,” Mr Dowd adds. “It has its advantages in terms of proximity to opportunities. Our ethos is that they should be proud to be here - that in itself gives them self-belief and the confidence to go on and achieve.”

It is projects of this type that will eventually help young people from poorer backgrounds to smash the glass ceiling blocking their career aspirations, according to last year’s report on social mobility by former Labour Cabinet minister Alan Milburn. The former health secretary says “a closed-shop mentality” prevents young people from low-income families from accessing the most prestigious professions.

“It has long been recognised that the UK is a highly unequal society in which class background still too often determines life chances,” the report says. “Our society will not flourish unless people feel that effort and endeavour are rewarded.”

The report says that schools play a key role in helping to open doors. One of the first tests is the exams at 16. Without these qualifications, university and a professional career can slip away.

Yet only 34 per cent of pupils from lower socio-economic groups achieve five good GCSEs, compared with about 65 per cent of their more affluent peers, according to government figures. Among those eligible for free school meals, the figure falls to just 22 per cent.

As well as academic results, the report highlights the importance attached by employers to so-called soft skills such as teamwork, leadership and presentation.

At Nottingham High, a private school whose former pupils include former Schools Secretary Ed Balls, another Labour leadership contender, it takes pride in its extra-curricular opportunities. “The school is a bit like a sushi restaurant,” says headmaster Kevin Fear.

“All the different options go round and round and the boys pick out what they like. They find their own route through the school according to their interests.”

As well as after-school groups, the school offers 16 activities every lunchtime, ranging from orienteering to more traditional sports and debating clubs. Crucially, the boys themselves take on responsibility for these clubs, which helps to develop their leadership and communication skills.

The approach has held former pupils in good stead. Ken Clarke, the current Justice Secretary and former education secretary, was a member of the CCF and was on the committee of the school debating society, where he once proposed a motion that “this house prefers despotism to democracy”. He was defeated. He was also captain of the Fives Club, which promoted the traditional handball game, treasurer of the history society, and a keen member of the school’s locomotive society.

A generation later, Mr Balls and Ed Davey, a Lib Dem MP and junior minister at the Department for Business, Innovation and Skills, also benefited from the opportunities on offer at the school. Both enjoyed responsibility through being house captains, while Mr Davey went on to be head boy. Mr Balls took his Duke of Edinburgh awards and was a member of the school orchestra; Mr Davey was chair of the debating society.

“There is an inevitable focus on celebrity, but a tiny minority of our boys go on to be in the public eye,” Mr Fear says. “It is more important to us that when one of our former pupils goes to an interview, they come across as grounded, well-rounded individuals who know how to communicate effectively without being arrogant.”

By instilling confidence - through giving pupils the responsibilities, activities, opportunities and reassurance they need - alumni typically find success in later life, Mr Fear adds. But some schools are either unable or unwilling to make such resources available.

“When I was at school, we were told that we were to be `hewers of wood and drawers of water’ or `the scum of the earth’,” says one state-educated teacher, who asked to remain anonymous. “I think most of us went on to fill these roles well enough.

“Given that private-school pupils are told throughout their school years that they are the future leaders of society, is it any surprise they go on to fill those roles?”

Schools need to create a culture in which talented pupils have the ambition and ability to aim for top jobs, headteachers say. But pupils - especially those who have no family history of higher education - also need to be imbued with a sense that their aspirations are achieveable.

Introducing politics and debating to young people is a good way of whetting their appetite for a career in public life. At Highgate School - a north London independent which boast five current MPs among its former pupils - in addition to offering A-level politics, aspiring MPs can join the politics and debating society. There is a steady stream of visiting MPs, regular trips to the House of Commons and a Youth Parliament annual debate.

“It is a hardwiring of opportunities and extra-curricular activities that really makes the difference,” says headmaster Adam Pettitt.

Private-school pupils, parents and staff are lucky enough to be part of a “virtuous circle”, explains Bernard Trafford, headteacher of the independent Royal Grammar School in Newcastle. “Parents have high expectations because they are paying and they expect the best. That, in turn, is what the school delivers. Their children pick up on this and believe the sky is the limit. They succeed as a result.”

But embedding self-belief in a school’s DNA does not happen overnight, he adds. It takes time, a shift in culture and a willingness by staff to go the extra mile in terms of providing extra-curricular activities.

At the Sutton Trust, Dr Elliott Major does not believe state schools need to “ape” their private-sector counterparts, but he is in favour of borrowing the best aspects of the private-school system, such as unremittingly high expectations of behaviour and performance, which in turn make underachievement unacceptable.

“If we don’t do this, Parliament will be incredibly unrepresentative of the very people it is meant to serve,” he says. “That surely must be a bad thing.”

But once the basics are firmly in place, success is self-perpetuating - fuelled by the pupils themselves. With hard work thrown in, there should then be nothing to stop a state-school pupil eventually taking their rightful place alongside the Michael Goves, David Camerons and Nick Cleggs of this world.

WHO WENT WHERE?

Eton College, Windsor (ind): 20 MPs

Highgate School, north London (ind) 5 MPs

Millfield School, Somerset (ind) 5 MPs

Westminster, central London (ind) 5 MPs

Nottingham High School (ind) 4 MPs

Reading School (state): 4 MPs

Source: The Sutton Trust; The Educational Backgrounds of Members of Parliament in 2010

WHAT MAKES A GOOD LEADER?

- A passion for your specialism: enthuse and inspire those within and beyond your organisation.

- Proven achievement: translating vision into action.

- Self-awareness: recognising your strengths and the gaps in your experience, and identifying clear personal objectives.

- Motivation and a sense of purpose.

- Effective communication: in writing, speaking and in groups; competent with technology, skilled in presentation and negotiation, and sensitive to others’ interests.

- An enquiring mind: the capacity to reflect, learn and have interests beyond your current specialism.

- Sound judgment: analyse complex information, assess risk and make choices and decisions.

- A team player: the ability to motivate and develop others and set high standards for yourself and others.

- Flexibility: ability to think laterally and creatively to solve problems.

- Integrity: demonstrate honesty, authenticity, humility and openness.