Gas Safety Certificates
Until 31st March 2009 gas safety inspections were carried out by CORGI registered engineers and a certificate issued. From 1st April 2009, gas safety testing must be carried out by a Gas Safe registered engineer.
For Practices in rented premises, the Landlord must arrange for a gas safety inspection annually, and must provide you with the Gas Safety Certificate.
More information:
HSE information for Landlords on gas safety - 
Gas Safe information for Tenants - 
Gas Safe information for Landlords - 
Link
won't open?