Bells were a compulsory requirement on new bikes sold in the UK until 1983 when they were scrapped by the Conservative government under Margaret Thatcher. However, in May 2004 it was again made a legal requirement to sell new bikes with bells installed, even though the new owner could remove the bell as soon as they had purchased a bike. This law was again scrapped in December 2011 under a government initiative called the Red Tape Challenge which aimed to quash over-regulation. So it is now personal preference as to whether the owner of a new bike would like to add a bell.
Apart from being incredibly useful at notifying other road users as to your existence, the humble bell has also become a fashion statement. Cannondale got in on the act with team rider Peter Sagan in 2012 when he was photographed with his new Cannondale Panic Bell, but it was a hugely successful 2013 Kickstarter campaign by Spurcycle for the Raw Bell and Black Bell which spawned a new generation of high-end bells… one of which was the King Cage BarBell which doubles as a shot glass!