This petition is to remove prescription charges for adults with cystic fibrosis:
petitions.pm.gov.uk/Cystic-Fibrosis
Currently sufferers of a range of permanent conditions (e.g. hypothyroidism) get free prescriptions for life (for everything, not just for that condition). But sufferers of other conditions (including cystic fibrosis) don't, and have to pay for their prescriptions.
I am dubious about the actual value of those petitions.pm.gov.uk petitions, but this one is at least worth some attention.