South Kensington is a mile and a half of museum, arranged more or less in a line. The walk is for the rainy Saturday you didn't plan for. Three kilometres in total, ninety percent of it indoors if you duck smartly between buildings.
Start at the V&A, not the Natural History. The V&A is London's most under-appreciated free museum — the cast courts alone would be a whole afternoon in a lesser city. The cafe is the first museum restaurant ever built and it's still the best.
Cut north through the tunnel to the Natural History — do the main hall for the whale, then leave. The queues for dinosaurs are a tax on the parents of under-sevens.
Science Museum next. Skip the noisy ground floor and head up to Making the Modern World, which is the single room I would take an alien to if they wanted to understand the last two centuries.
Out across the road, past the Albert Hall (lap its red terracotta, don't go in), and finish through Kensington Gardens to the high street tube.
