For all the convergence between UK and US rivals – similar profits, closing salaries and identical use of marketing speak – culture clashes can still crop up in the London offices of US law firms.

The shocked chairman of one US practice visiting his City subjects some time ago reportedly wondered if it was simply a “cultural thing” when he discovered vending machines in the toilets dispensing painkillers, toothbrushes and that indispensable client-winning item, the condom.