On Ubuntu, if you set the time manually using
sudo locale-gen en_GB.UTF-8
then the problem is that it does not take BST (British Summer Time) into account, so during BST the server time is out by 1 hour. This is obviously an issue if you have time restrictions on logging on to whatever system is hosted on the server.
The solution is to run:
sudo dpkg-reconfigure tzdata
Follow through the on-screen prompts to set the locale to Europe and then London this then solves the issue, and the server automatically stays at the correct time when the clocks change.