The 1571 feature was introduced by BT Group to the UK in the 1990s after they digitised all the telephone exchanges.
In 2007 a charge of £1 was introduced for any month in which two chargeable calls are not made on the line (this might apply, for instance, to people who have Carrier preselect with another telephone company).
To indicate to called parties that they have waiting messages, the exchange sends an interrupted dialling tone to them when they take their telephone off-hook.
Another service was withdrawn in March 2009: 1571 Online allowed customers to retrieve their stored messages via the World Wide Web.
Neither of the services can be disabled or re-enabled by the user, but must be cancelled or ordered, with a lag of several days.