Official UK company registry (Companies House). Two modes: pass query to search companies by name (returns company number, name, status, type, incorporation date, address), or pass companyNumber for the full registry profile — legal name, status, company type, jurisdiction, incorporation/cessation dates, SIC activity codes, registered office address, accounts (next due, last made-up-to), confirmation-statement due date, charges and insolvency flags, previous names, and the officers list (name, role, appointed/resigned dates, nationality, occupation). Free, Open Government Licence (commercial use permitted). The authoritative UK-company KYB lookup — complements business.lei (GLEIF) and business.br-cnpj (Brazil).