The British Beer and Pub Association (BBPA) & Society of Independent Brewers (SIBA) maintain an informal container colour band registration scheme on behalf of UK brewers.
The colour band combinations are created using colours and is a voluntary system with the aim of avoiding duplication. The BBPA and SIBA cannot be held responsible for any errors or misunderstandings arising from the sorting/collection of containers.
Colour bands should be regarded as an aid to identification and not a definitive system.
Containers should be identified by all means available, i.e. brewers name stamped on container, product labels etc.
You can find the container database here.