Ditch your French and German textbooks and start learning Mandarin, David Cameron told the UK’s school pupils after his return from a visit to China last week.

The UK prime minister should be happy with any language skills his young compatriots manage to pick up. But it is true that it would be useful if more people spoke the main language of the world’s soon-to-be largest economy.

I asked China-based colleagues if they knew of any foreign business leaders who spoke Mandarin. The list was short and limited to executives working in China. Roland Decorvet, the Swiss head of Nestlé in China, speaks fluent Mandarin. Peter Humphrey, the British fraud investigator who did work for GlaxoSmithKline and who has been detained by the Chinese authorities, also speaks excellent Mandarin.