The CMS protects members. It registers schemes, approves annual contribution increases, enforces solvency requirements, investigates complaints, and publishes industry data. Every scheme rule change, new plan, and benefit amendment must be approved by the CMS before it takes effect. If you have a dispute with your scheme that customer service can't resolve, the CMS adjudicates it.
SA example: In 2025 the CMS recommended schemes cap 2026 increases at CPI plus a reasonable margin; schemes that wanted to exceed that had to justify it to the regulator and to members.