Demon were founded in 1992 and have become one of the UK's largest Internet Service Providers. You may have noticed they have also sponsored the Fulham Football Club in the past. Demon offer web hosting, leased line provisioning, ISDN access, electronic commerce services, dial-up access, dedicated game servers, and a full Usenet newsfeed.

Demon are one of the oldest ISP's still in operation, and were particular popular during the days of dialup connection prominence in the late 1990's. Demon were bought in 1998 by Scottish Telecom, and the founder of Demon, Cliff Stanford, went on to create the company Redbus. Demon, however, still retain the 666 code for it's access numbers.

Scottish Telecom rebanded the company Thus plc in 1999, and recently sold the company to Cable & Wireless in 2008.