Londoners traveling on the city's often overcrowded Underground subway system are not known to be particularly outgoing, but there's a campaign afoot to change that.

An unidentified group is giving out Tube Chat badges encouraging people to strike up conversations with their fellow passengers. They've already earned the ire of Transport for London, which said Thursday it is unhappy that the group has used the Underground's official logo on the badges without permission.

The transport agency said the idea is "interesting" but they don't want users to be confused by the use of the familiar logo.

The badges are being distributed with a flyer stating people will benefit from a daily chat.

The transport agency does give out "Baby on Board" badges to help pregnant women get seats.