When David Marland stepped off the plane at Gatwick Airport last week, he knew he had to call the doctor.

For the past decade the British mathematics teacher has lived and worked in Wuhan, the Chinese city at the centre of a dangerous epidemic that shows few signs of slowing down.

What’s more, Mr Marland lives only five minutes from the seafood market suspected to be the source of the virus, and walks through it nearly every day. Indeed a coronavirus case was recently confirmed in his apartment block.

But when he called the NHS 111 helpline, as suspected carriers have been advised to do, the answer was unexpected.

Instead of being called in immediately for a test, he says he was asked only if he had “the sniffles”. When he replied in the negative, the specialist on the other end of the line told him to call back if he started feeling unwell. With that, the conversation was over.