If you're writing for British clients or audiences and want to sound like an actual professional rather than either an American startup or a Dickens character, this gets the tone right. It handles EN-GB spelling (colour, organise, centre), kills reflexive Americanisms (no "reach out" or "circle back"), and maps formality to context with specific guidance on greetings and sign-offs. The avoid lists are honest about both corporate jargon and forced Britishisms. Works for emails, proposals, client comms, anything where sounding naturally British matters. The examples show restraint without stiffness, which is the whole point.
npx skills add https://github.com/jezweb/claude-skills --skill uk-business-english