Affected users will not be able to log in and will receive an e-mail instructing them to reset their password.

CNN: Twitter hacked; 250,000 accounts affected

The networks are now available for U-verse TV customers, who already receive the service at home, when they log-in to the site.

ENGADGET: AT&T U-Verse iPad app adds more streaming video, new sports and sharing features

The two million people already signed up to the London 2012 ticketing database will receive information about how to apply, with registered users being able to use their existing log-in details.

BBC: London 2012 Olympic tickets on sale 15 March