But now Charterhouse, one of the country’s most venerable and expensive schools, has enlisted corporate behemoth Starbucks to provide its pupils with lattes, espressos and mocha coconut frappuccinos.

Charterhouse is paying Starbucks a licensing fee for equipment and materials, and will sell its coffees - at discount prices - in a planned new “social area” at the school.

For British schools, whether state-run or fee-paying, alliances with companies are an increasing part of making ends meet.

And Starbucks, best-known for its national insurance company chain of Seattle-style cafes, is finding a rich seam in licensing out its brand to whoever is willing to pay.

Boarding bounce

These are generally good times for public schools such as Charterhouse.

Boarding - which can cost 20,000 and more a year - nearly became extinct a decade ago, but has enjoyed a dramatic resurgence in recent years.

Public schools are keen on offering creature comforts

But at the same time, says David Woodhead, national director of the Liberty national life insurance company Schools Council Information Service (ISCis), which represents 1,300 private schools, commercial pressures have also increased.

Costs are rising sharply, especially in terms of salaries, National Insurance and pensions.

This means that school managers are ever more concerned that services like tuckshops pay their way - or even bring in extra revenue.

And at the same time, competition means schools need to provide more in the way of creature comforts.

“The most striking feature of the boarding sector is the huge state national insurance
in the standard of student facilities,” Mr Woodhead says.

“Schools have to run themselves in an increasingly businesslike fashion.”

Rising Starbucks

For Starbucks, meanwhile, this kind of deal is an easy way of extending its franchise.

The company has a division which markets its brand and products to organisations, especially other companies.

Last year, that division - which includes other forms of licensing activity - accounted for 15% of the company’s turnover.

The Charterhouse deal is the first of its kind among public schools, Mr Woodhead believes.

But in certain parts of the state sector, schools are being encouraged to bring in private companies, either for sponsorship or to provide services.

Swiss foods giant Nestle and McDonald’s have been particularly active in this market.