Companies House Disqualified directors database, their magazine, and information on company registration. Also has an online version of their journal the Register with e.g. Companies House statistics. Search company database by company name or registration number. Searches current, dissolved, previous and proposed names. List by region and rank by sales or employees.
Registration is required in both cases.
There is also information on business expectations, business failures etc. An electronic version of BT's Yellow Pages directory, listing contact details of over 1.6 million UK businesses. Searchable by location or category, plus company name. Hoovers's Online UK Lists about 400 UK companies with some financial information, link to web site, key executives etc. Kelly's Directory of 143,000 companies, giving contact details.