Britain's biggest Internet Service Provider, AOL UK, has signed up its 500,000th member.

Its subscriber numbers have risen more than 75% in the last year and it has outstripped its stablemate Compuserve, the number two ISP, which has 400,000 members.

No.1...and advertising the fact

Demon Internet comes next with 250,000 members, then BT Internet with 165,000, MSN with 160,000 and Virgin Net with 145,000. Dixons' Freeserve and X-Stream, two newcomers offering a free ISP service, are estimated to have quickly acquired about 120,000 members each, according to Fletcher Research.

AOL UK was launched in January 1996 as a joint venture of America Online and Bertelsmann AG, Europe's largest media group.

"No other service can offer our content, community and ease of use. AOL UK is attracting a broad base of mass market consumers with many of its new members having just purchased their first computer in order to go online," said managing director Jonathan Bulkeley in a statement on the latest figures.

Major ad campaign launched

On Monday, AOL launched a £6m advertising campaign with its first spots on national television, as well as posters on London Underground and advertisements in the press and on radio.

The television version shows the Internet being accessed in an ordinary living room and reflects AOL's belief that a mass market is now developing for it to exploit. The ad features a "genie" called Connie, who emerges from a computer screen to help guide a family around AOL.

The AOL ad celebrating its 500,000th member appearing in national newspapers is a blunt rebuttal of Demon's claims to be the number one ISP. "No argument. No dispute. No contest. No.1", it says.