The Smoke Control Areas (Exempted Fireplaces) (England) Order 2005
Section 20 of the Clean Air Act 1993 prohibits the emission of smoke in smoke control areas. The Secretary of State may by order made under section 21 of the Act exempt specified classes of fireplace from the provisions of section 20, if she is satisfied that they can be used for burning fuel other than authorised fuels without producing any smoke or a substantial quantity of smoke.