The amount of packaging material used must not be excessive and should be limited to a minimum to maintain the necessary level of safety, hygiene and acceptance for the packed product and for the consumer. Containers should not mislead consumers as to the amount contained in them and should not have false bottoms, be double skinned or be under-filled.
Additionally packing materials must not contain polluting heavy metals.
The Department for Business Innovation & Skills has produced a booklet which summarises the operation of the law in the UK. Click on Packaging Essential Requirements see the guide.