"Parents will have serious questions for the Prime Minister about opening up schools to overseas pupils".
Excluding overseas pupils, 490,000 British residents are currently attending independent schools, compared with 491,000 in 2008.
Many boarding schools rely on an intake of overseas pupils and a strong EAL department is essential to making a success of this strategy.
Boarding schools today welcomed a reversal of 20 years of decline with the announcement that numbers rose by 1%, with around 8,000 new overseas pupils admitted.
British independent schools are recruiting strongly abroad and estimate overseas pupils - more than 16,600 in total - bring in at least £271m per year in currency earnings.
Last month figures from the Independent Schools Council revealed a stunning increase in the number of Russian pupils studying at UK private schools, up from 816 in 2007 (3.9% of all overseas pupils) to 2,150 in 2013 (8.3%).
China and Hong Kong provide more than 10,000 of the 27,000 overseas pupils attending British independent schools in 2015, with Russia the next largest contingent with 2,800, followed by Germany with 1,900 and Spain with 1,200.
At the same time that she was delivering her rather pointless alert, delegates at the HMC gathering were announcing that their fees are set to "soar" in a "race to attract overseas pupils".
The report, prepared by Oxford Economics, said that ISC-affiliated schools received £685m in annual fees from 25,700 overseas pupils – nearly 40% of them from Hong Kong and China – meaning that the private school sector gained more than 10% of its turnover from 5% of its pupils.
Perhaps the first overseas public school pupils of all were the four Russians who arrived in England in 1602 to learn English, visiting Eton and Winchester, with the aid of Giles Fletcher, England's erstwhile ambassador to Moscow and an Old Etonian.
