Gas safety certificate (CP12/LGSR): how to store and send to customers

What is a CP12 / Landlord Gas Safety Record?

A CP12, formally known as a Landlord Gas Safety Record (LGSR), is the document issued by a Gas Safe registered engineer following a gas safety inspection of a rental property. The "CP12" designation refers to the old British Gas form number and has stuck as industry shorthand, though the formal document is now the LGSR.

It is a legal requirement under the Gas Safety (Installation and Use) Regulations 1998. Landlords must arrange an annual gas safety check for every gas appliance and flue in their rental property, carried out by a registered engineer, and hold a valid LGSR at all times.

What the certificate must include

The LGSR must record:

• The address of the property inspected
• The date of the inspection
• The name, Gas Safe registration number, and signature of the engineer
• A list of every gas appliance inspected
• The result of each appliance's inspection (satisfactory, immediately dangerous, or at risk)
• Any defects found and the remedial action taken or recommended
• The operating pressure and heat input/output where applicable

The 28-day landlord obligation

Once you issue a Gas Safety Record, the landlord has a legal obligation to provide a copy to existing tenants within 28 days of the inspection. New tenants must receive a copy before they move in. As the engineer, your responsibility is to complete the record accurately and provide it to the landlord promptly — ideally the same day as the inspection.

Some engineers send the completed LGSR by email immediately after the inspection using a digital form on their tablet or phone. This is best practice and far more professional than posting a paper copy days later.

Retention requirements

You are legally required to keep a copy of every Gas Safety Record you issue for a minimum of 2 years. The landlord must also retain records for 2 years.

In practice, keeping records for longer (5+ years) provides additional protection if a dispute arises years after the event. Digital storage makes this straightforward.

Digital vs paper copies

Paper records are increasingly impractical. They can be lost, damaged, or illegible. A robust digital system means you can retrieve any certificate in seconds if needed for an insurance claim, HMRC enquiry, or legal dispute.

Effective digital storage options include:

• A dedicated cloud folder organised by property address (Google Drive, Dropbox)
• Trade management software with built-in document storage
• Dedicated gas engineering apps that produce and store LGSRs automatically

Sending certificates professionally

A PDF sent by email on the day of inspection is the professional standard. Include the certificate as an attachment with a brief covering message confirming the inspection outcome and any recommendations. This creates a clear paper trail and gives landlords what they need to comply with their obligations quickly.

For landlords managing multiple properties, organising your certificates by property address with consistent file naming (e.g., "LGSR_22-Maple-Ave_2025-05-10.pdf") makes you significantly easier to work with — and easier to retain as their regular engineer year on year.