LONDON — Despite its policy of disallowing children younger than 13 to sign up for accounts, the obscenely popular micro-blogging service Twitter is taking it on the beak for pointing minors in the direction of pornography.Members of Parliament, led by Tom Watson, the minister for digital engagement and the U.K.’s most active tweeting politician, are calling for Twitter to require age verification and police users for inappropriate behavior. No one is asked their age before they sign up, Watson said — in fact, the notice that users must be older than 13 is barely noticeable. In addition, most accounts are held by anonymous users who shield their real email addresses, so no one even knows who they really are. Those nagging details, combined with adults’ fondness for linking to pornographic images from their tweets in violation of Twitter’s terms of service, compose a recipe for disaster, Watson said.

According to New Media Age magazine, escorts frequently use Twitter to update clients about their locations and often post links to explicit photos and videos. One Facebook group encourages escorts to hawk their wares via Twitter because the service is un-moderated and uncensored.

“Twitter is a relatively new but fast-growing company,” Watson told New Media Age. “If it wants to maintain its reputation for quirky micro-blogging, it would be well served by sorting out its house rules on this sort of thing.”

Fellow MP John Whittingdale added, “If Twitter is to be successful, it’s in its interests to make sure it’s policed. Young people will always sign up to these sites, but other social networks actively identify people who are underage and remove them.”