The use of slug pellets which contain the toxic chemical metaldehyde will be banned from March 2022. Although metaldehyde pellets were banned last year, DEFRA was forced to rescind the ban because of a procedural error.
Metaldehyde is a particularly nasty poison, which poses risks to off-target species such as birds and mammals. Used heavily by farmers, the poison also poses the risk of run-off into freshwater bodies such as rivers, streams and ponds, affecting their fragile ecosystems.
Sadly, it will still be legal to sell metaldehyde products until 31 March 2021, with their use allowed for a further 12 months until 31 March 2022. Because of the danger to pets and birds, gardeners who have small quantities of product remaining are advised not to dispose of them at home, but to take to a local authority waste facility.
Organic growers would never use metaldehyde pellets. See here for how to prevent slug and snail damage in your patch. Traps, barriers and biological methods can help control the pests. Pellets should be used only if absolutely necessary, and be sure to buy those which are certified for use in organic systems. These contain ferric phosphate, which affects the gut system in the mollusc, causing it to stop feeding. However, these too can have an off-target detrimental effect on earthworms.