Planet was the UK's last manned lightship having served in Liverpool and later in the Channel Islands. The ship was built and launched in Liverpool in 1960 and served as the Mersey Bar lightship until 1972. After leaving BAR station Planet was sold to Trinity House and headed south serving until 1989 at CHANNEL station. Planet was then sold and has been restored to its original condition, arriving at its current berth at Liverpool's Albert Docks in 2006. Planet is now open to the public as a cafe and a museum.
Lightships are ships which act as lighthouses of course. They were used where the waters were too deep or conditions were unsuitable for building a permanent lighthouse. Most lightships have been replaced by permanent structures or buoys nowadays but there are still a number of unmanned lightships around British waters.