The standards on enclosure sizes in the code are being phased in over a 12-month period from 1 January 2013. You have until the end of 2013 to ensure your reptiles are housed appropriately. After this time, minimum enclosure sizes will become mandatory.
The minimum enclosure size ensures captive reptiles have enough space to move around, perform natural behaviours and avoid cage-mates if housed in groups. Enclosures that are too small can lead to a variety of physical and behavioural problems in reptiles. Small enclosures also make it more difficult for keepers to provide their animals with an appropriate environment (e.g. a thermal gradient).