There is a lot of mis-information and ignorance around this topic so here is a quick guide.

Gas safety in property is covered by the Gas Safety (Installation and Use) Regulations 1998

Duties of landlords are covered in Part F, Regulation 36 (found here)

Very briefly the regulations require that every landlord shall ensure that:

* there is maintained in a safe condition any relevant gas fitting and any flue which serves any relevant gas fitting;

* each appliance and flue to which that duty extends is checked for safety within 12 months of being installed and at intervals of not more than 12 months since it was last checked for safety;

* a record in respect of any appliance or flue so checked is made and retained for a period of 2 years from the date of that check;

* any work in relation to a relevant gas fitting or any check of a gas appliance or flue carried  is carried out by, or by an employee of, a member of a class of persons approved for the time being by the Health and Safety Executive;

* a copy of the record is given to each existing tenant of premises to which the record relates within 28 days of the date of the check;

* a copy of the last record made in respect of each appliance or flue is given to any new tenant of premises to which the record relates before that tenant occupies those premises.

It is as simple as that.