The Building Societies Act 1986 establishes the Building Societies Commission to regulate societies whose principal purpose is raising primarily member funds for advances secured on land for residential use. It prescribes incorporation, powers (including adoptable powers), capital and liquidity requirements, classification of advances (class 1–3), limits on non‑retail funds and deposit/share proportions, valuation and custody duties, and creates the Building Societies Investor Protection Board with a levyable fund for defined insolvency payments to protected investors.

The Act gives the Commission extensive supervision, investigation and enforcement powers — imposing conditions, prohibition orders, authorisation revocation and court recourse — with statutory appeal routes. It sets governance and director duties, accounting and audit standards, complaints and dispute schemes, and detailed regimes for voluntary and court winding‑up, amalgamations, transfers of engagements and transfers to companies, and allows recognised providers to offer conveyancing and related services.