The previous answers are pretty much on the mark. Having spoken about this with various councillors, the problem is partially with the automatic sorting equipment and partially with the contract Lewisham negotiated.

The trouble is that if there is too much 'contamination' (i.e. plastics other than bottles, shredded paper, garden waste, black bags etc) then the whole load is rejected by Veolia and goes to SELCHP for incineration. So unfortunately, while you may feel that you are doing your bit by putting all type 1 and 2 plastics in, or by putting your shreddies in a Primark bag, your actions are actually resulting in lower recycling rates.

I understand that the recycling contract is up for renewal and would urge you to write to your councillors and Susan Wise (as Cabinet Member for Customer Services) urging them to increase the range of articles to the same as Southwark, who use the same facility. They can recycle shreddies, so we should be able to as well.

Southwark also have a useful page describing all article that can be recycled and how to recycle them.