The Gas Safety (Installation and Use) Regulation 1998 deal with the landlords' duties regarding gas safety.
A landlord is responsible for ensuring that an annual gas safety check is carried out by a Gas Safe registered engineer, this will include a check of any gas appliances, flues and pipework. You must keep a record of the safety check for at least 2 years and issue a copy of the gas safety certificate to each existing tenant within 28 days of the check being completed and issue a copy to any new tenant before they move in. The ULHS also advise that you fit a Carbon Monoxide detector in the property.
All Gas Safe registered engineers will carry an ID card. you can also confirm or find a Gas Safe registered engineer on the Gas Safe Website www.gassaferegister.co.uk
Failure to comply with these regulations is a criminal offence and landlords who don't comply could receive an unlimited fine and/or custodial sentence.