They do their best to hide it away, but here it is:
HP Planet Partners printing supplies return and recycling programme for the UK.
Home users can order up to 10 free pre-paid envelopes for the return of used ink cartridges. BB has just put an order in (after all, HP’s advanced technology means that lots of used cartridges are generated). It would be nice if HP tracked the returns and sent a discount voucher after every ten or so.