How many letters does the top answer for “capital of the united kingdom” have?

The most common answer is london (6 letters).

Crossword clue: capital of the united kingdom

1 answer found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

london 6 letters wd-fact

the capital and largest city of England; located on the Thames in southeastern England; financial and industrial and cul

a division of the united kingdom 50% similar → england

a person from united kingdom 50% similar → british, briton

capital of kingdom of denmark 50% similar → copenhagen

capital of kingdom of romania 50% similar → iasi

capital of kingdom of the netherlands 50% similar → amsterdam

currency of united kingdom 50% similar → pound

dish from united kingdom 50% similar → bangersandmash, bubbleandsqueak, cheeseontoast

united kingdom (abbreviation) 50% similar → uk