Blue hour in London

The river does the work: South Bank toward Waterloo and the City, Tower Bridge from the east, Millennium Bridge as a leading line. After rain the Embankment is better than a clean sunset — double the lamps. Canary Wharf and the bridges at Greenwich are the modern version of the same idea: glass and warning lights against a blue band.

London cloud does not always kill blue hour; a thin lid can still go cobalt. A thick one will not. Check the calculator for the day you actually have, in Europe/London (GMT or BST).