CP12 renewals: the 2-month rule that keeps your renewal date fixed

The rule in one sentence: if the annual gas safety check is carried out in the two months before your current record expires, the new record still runs from the old expiry date - so renewing early costs you nothing. Renew earlier than that two-month window and the twelve months restart from the day of the check, quietly dragging your anniversary earlier every single year.

Why the date creeps, and why it matters

Most landlords book the engineer when it's convenient rather than when it's due. Do that three years running - a month early here, six weeks early there - and a check that used to fall in March is now happening in December. Nothing illegal has happened; you've simply given away three months of certificate every year, and you're paying for a check sooner than the law requires. The two-month rule exists precisely so you don't have to leave it to the last minute to avoid that.

A worked example

Your current record expires on 14 March. The engineer comes on 2 February - inside the two-month window, so the new record runs to 14 March next year. Same job done on 5 December instead is outside the window, so the new record runs to 5 December next year and you've lost three months. Same engineer, same price, three months' difference.

The two dates people forget aren't the expiry

• The tenant copy: an existing tenant must be given the record within 28 days of the check, and a new tenant must have it before they move in.
• The retention duty: keep each record for at least two years, which in practice means keeping the previous one as well as the current one.
• The check itself covers every gas appliance, pipework and flue - and it must be carried out by a Gas Safe registered engineer, whose registration number appears on the record.

This is a criminal regime as well as a civil-penalty one: gas safety breaches are enforced by the Health and Safety Executive and can lead to prosecution as well as any action your council takes. It is not a duty to be casual about - but it is also one of the easiest to get permanently right, because the dates are entirely predictable.

Do this once and it stops being a problem

• Write down the expiry date on your current record - not the date the check was done.
• Diarise a booking reminder for six to eight weeks before that date, so you land inside the two-month window without cutting it fine.
• Log the date and method you gave the record to your tenant, alongside the record itself.

Sources: Gas Safety (Installation and Use) Regulations 1998, regulation 36 (including the early-renewal provision in force since 6 April 2018) · HSE landlord gas safety guidance. General information, not legal advice, as at August 2026.