The Goring Hotel does proper afternoon tea for £58 but it's worth it. Royal warrant holders, they supply the Queen. Book weeks ahead.

For budget options: The Wallace Collection café in Manchester Square does afternoon tea for £25 in a gorgeous covered courtyard. Museum entry is free.

Avoid anywhere advertising afternoon tea for under £20 — It'll be sad sandwiches and packet biscuits. But when you find the right place, even expensive can be genuinely worth the splurge.