How many letters does the top answer for “an isle and county of southern england in the english channel” have?

The most common answer is wight (5 letters).

Crossword clue: an isle and county of southern england in the english channel

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

wight 5 letters wn-def

an isle and county of southern England in the English Channel

a county in southern england 50% similar → berkshire, hertfordshire