Check your council's hard rubbish rules first
Some councils do accept mattresses as part of a booked hard rubbish collection (see our hard rubbish guide), often with a limit on how many per booking. Others exclude mattresses specifically and direct residents to a separate drop-off or paid collection instead — this is genuinely inconsistent between councils, so it's worth checking rather than assuming either way.
Dedicated mattress recycling
A number of waste transfer stations and dedicated mattress recyclers accept mattresses specifically, since the springs, foam, and fabric can mostly be separated and recovered rather than landfilled whole. Where available, this is usually a small fee, less than the cost of illegal dumping fines if a mattress is left somewhere it shouldn't be.
Buying a new one? Ask about take-back
Many mattress retailers will remove your old mattress for a fee (sometimes free) when they deliver a new one — worth asking at the point of sale rather than arranging disposal separately afterward.