A public school for the public is how one sixth-former describes Christ’s Hospital, a co-educational boarding school near Horsham, where the pupils are instantly recognisable from their distinctive uniform - ankle-length clerical cassocks with bright yellow stockings for the boys.

It’s a well-worn British truism that public schools are only for those who can pay. Out of the hundreds of independent schools originally founded to provide a free education for the bright children of the deserving poor, most now charge fees upwards of Pounds 10,000 a year and scholarship places tend to be open to all contenders, regardless of need. Only a handful still struggle to honour the aims of their founders.

Christ’s Hospital originates from the compassion of Edward VI, who was moved by the plight of the poor and homeless in London to establish it and two other institutions - St Thomas’ Hospital and Bridewell Hospital, a centre for training “idell vagabonds” to become industrious apprentices, which later became King Edward’s School, Witley.

In 1552, Christ’s Hospital opened in London with 260 pupils, many “taken from the dunghill”. Today, the school still gives priority to children with “a need for boarding education” and includes girls who were first admitted in 1985. The governors define need in a number of ways; one pupil admitted recently fulfilled most of the criteria. She is one of four children in a single-parent family, living in a two-bedroomed flat in an inner-city high-rise block. Of her three siblings, one is asthmatic, one epileptic and the third has a serious hereditary illness.

Other pupils may have a parent who is an alcoholic or who is in prison, they may have been abused or they may find it impossible to get on with a step-parent. When the school is considering applications, these children will come top of the list.

“Our client le is totally different from a traditional public school,” says Richard Poulton, the headmaster. “At Christ’s Hospital, you have to stand everything you know about a typical public school on its head.” Although all pupils have to pass a standardised IQ and verbal reasoning test and must be at least “average” for their age group, nearly 70 per cent come from primary schools, not from exclusive prep schools. Many of the staff come from the state sector too.

Of the 820 pupils, 285 this year have parents who pay nothing towards the Pounds 11,000 annual costs; some of their fares are also paid to allow them to visit their children at school. All parents are means-tested; last year, only 17 paid full fees. But the school is keen to maintain its high academic reputation; within 10 years of its foundation in London, pupils originally destined for work in ale houses were winning scholarships to Oxford and Cambridge. Nowadays, 30 to 40 per cent of the children win places at Christ’s Hospital on the basis of academic merit - high expectations are still fulfilled with eight out of 10 pupils going on to university this year.

Like many public schools, tradition still plays an important part in school life. At 1.15pm sharp every day, the entire school forms ranks and, in strict time to the music of the school band, marches into lunch in the vast panelled dining hall. After the meal, pupils must take it in turns to clear and wipe the tables. This is known as “trades”, in memory of the time when Christ’s Hospital children were trained as apprentices and domestic servants.

The pupils say they don’t object to the marching or the uniform, even though they can get too hot in the summer. In the past the boys have had to shrug off taunts of “Paupers!” on the rugby pitch from pupils of other public schools. “We’re proud of the school and what it stands for,” says one senior boy.

The facilities are lavish, including a theatre, a Pounds 3.2 million sports centre and 200 acres of playing fields, as well as imposing red-brick school buildings, purpose-built nearly 100 years ago. The superficial differences are that the pupils don’t all talk with posh accents and the boys’ haircuts are not conventional.

“It would be a heavy burden for some of the pupils to have to return home in the holidays with a short back and sides,” explains Mr Poulton. He says the school does not want to make children ashamed of their backgounds, but to give them a springboard to opportunity. And he regrets that the policy of some local authorities to treat everyone equally prevents them from nominating certain children in need.

“We can give them structure and stability in their lives. A lot have to learn to trust again and some of the children bond together through sharing their family problems.” Counsellors regularly visit the school to work with pupils with particular difficulties.

Through group activities like drama and music, the school encourages children to work and live together harmoniously. When they first arrive, many are loners, unused to community discipline or even to sitting down to a meal with others.

“Some children take and take before they learn to give,” Mr Poulton says, explaining that the job can exact a heavy toll from staff, who also have access to their own confidential counsellor.

Christ’s Hospital is determined to maintain its original ethos, but the balance between charity and financial viability is increasingly hard to maintain. The all-boarding school receives Pounds 6 million a year from investments and its London properties, and costs Pounds 8 million a year to run about the same as six similar-sized comprehensives.

In the past, a scheme to attract more full fee-paying pupils met with such an outcry from staff and former pupils that it was swiftly dropped. Some old boys, or “Old Blues”, as they are known, also consider the income limit of Pounds 42,600 - which applies to two-thirds of parents - to be too high. The school’s justification is financial - less than 20 per cent of the running costs are met through fees. And the head argues that, for a family with several children, Pounds 11,000 a year represents a considerable sacrifice, even for someone with twice the average national family income. In fact, most children are from families with incomes of less than Pounds 14,000 a year.

The school now runs a commercial company; letting out the sports centre raises Pounds 100,000 a year and some land was recently sold to developers for retirement homes. Money is also raised through an extraordinary system for would-be benefactors who, after an unqualified donation of Pounds 12,000 or more, can be elected “donation governors” with the right to nominate one child “in need of a boarding education”. Currently there are 570 donation governors.

Like any school, serious financial pressures fall on the staff budget. Last year it had to replace three experienced staff with newly-qualified teachers, and next year might have to lose some staff and reduce the number of subjects offered.

Faced with similar pressures, King Edward’s School, Witley, established as part of the same foundation, nearly went under altogether.

Until the 1970s, King Edward’s only offered places to children who were orphaned, from single-parent families or whose parents worked abroad. Most were free places, with many children sponsored by their local authorities. It was hailed as “the public school of the future” after a visit by the Public Schools’ Commission, set up in 1965 by the Labour Government to examine the independent sector.

Then calamity struck. An ambitious building programme of new boarding houses coincided with a slump in the property market, so the school could not cover the costs by selling its original London site to finance the scheme. By the late 1970s, local authorities could no longer afford to subsidise pupils and, with a vastly reduced income, the school had to take day pupils for the first time, and judge pupils’ eligibility by their parents’ ability to pay.

The governors took fee-payers with a terrible sense that they were betraying the Royal Charter,” says Rodney Fox, the current head. But they were determined the school should remain a charity and, after a successful appeal and some astute financial management, the school is once again offering bur-saries to half of its 400 boarders; about 100 attend free.

Pupils with family problems once again get priority, although help is now also extended to able pupils whose parents cannot afford the fees. The assisted places scheme pays the tuition fees of some children, but this is mainly based on need and not on outstanding academic ability.

Mr Fox believes that opening the school to some fee-payers has advantages. “King Edward’s is now more outward-looking; we’ve had to respond to the needs and wishes of parents,” he says. “We like parents to have a stake in their children’s education so that they feel they can complain if they want to. ”

Mr Fox admits that there can be a price to pay for removing disadvantaged children from their home environment. “We are offering these children an incredible chance in life, but this may open up a gulf between them and their families later.”

The future now looks bright. The school still owns some “worthless marshland” in Wapping donated by Charles II, and is hoping to increase the number of free places, although the abolition of the assisted places scheme by a future Labour government could limit its plans.

Labour has pledged to abolish the scheme so that the money can be redistributed among state schools although this would not affect pupils who already have assisted places. The only other concession is that schools which run into financial difficulties because of the scheme’s abolition may apply to be admitted into the state sector.

Both Christ’s Hospital and King Edward’s are keen to raise awareness of what they can offer. Mr Poulton recently invited 200 primary heads to visit Christ’s Hospital and Mr Fox regularly writes to education and dioscesan welfare officers about available free places.

“When you’re giving education away, you want to be sure that you’re giving it to the most needy, rather than the best-informed,” he says.

Those wishing to apply for places should write to the Admissions Officer, The Counting House, Christ’s Hospital, Horsham, West Sussex RH13 7YP. At King Edward’s 40 per cent of the pupils receive bursaries and almost all of these are considered to “need” boarding education. For an application form, write to the Headmaster’s Secretary, King Edward’s School, Witley, Godalming, Surrey GU8 5SG