It is the question I get asked most by landlords, usually while I am standing in an empty flat between tenancies. The short answer is not the one most people expect.
The short answer
There is no law in Scotland that says you must change the locks when one tenant leaves and another moves in.
No statute requires it. The Scottish Government’s model private residential tenancy agreement — the document most Scottish tenancies are built on — does not mention locks at all.
That surprises people. But “not required” and “not advisable” are two different things, and the rest of this is about the gap between them.
What the law does say about keys
The model agreement is clear on one point that matters here. A landlord may keep a set of keys, but it states plainly that the landlord has no right to use those retained keys to enter the property without the tenant’s permission, except in an emergency.
That sets the standard the whole question really turns on. Once a tenancy begins, the tenant decides who comes through that door. If a previous tenant, an ex-partner or a friend still holds a working key, that standard has already been broken — and nobody knows it.
The same agreement asks the tenant to take reasonable steps to secure the property if they are away for more than fourteen days, and requires your written consent before alterations. That last clause is the one a tenant falls foul of when they change a lock themselves without asking. I have written about that side of it in Tenant Lock Change Rights in Scotland.
The one place the law does demand locks
If the property is a flat in a tenement, there is a duty, and it is fairly new.
Since 1 March 2024, the Repairing Standard requires that common doors are secure and fitted with satisfactory emergency exit locks. Every common door has to be lockable, and the emergency exit lock must open from the inside without a key, so that nobody is trapped behind it in a fire. There is also a requirement for a secure entry system on the common front door, with an exemption for blocks of three flats or fewer where the occupiers can see the door.
I fit and repair the locks on communal stair doors. I do not work on door entry or intercom systems, so that part is one for a specialist. But the lock itself — and whether it lets people out in a fire — is a landlord duty worth checking before someone else checks it for you. If the property is licensed as an HMO there is more to it again, which I have covered in Your Guide to HMO Door Compliance in Scotland.
So why do most landlords change them anyway
Three reasons come up again and again.
Key control. You cannot prove a negative. A tenant may have had a spare cut for a partner, a cleaner or a dog walker, entirely innocently, and forgotten it years ago. Counting the keys back in tells you how many were returned. It tells you nothing about how many exist.
Insurance. A break-in with no sign of forced entry is a harder claim to make than one with a splintered frame. Policies vary a great deal on this, so read your own wording rather than assuming — but it is a real reason landlords change cylinders between lets.
Disputes. If something goes missing in the first fortnight of a new tenancy, the first question anyone asks is who had a key. A lock changed between tenancies answers it.
When I would tell you not to bother
I would rather say this than sell you a lock you do not need.
If you issued every key yourself, got every one of them back, and the tenant was someone you knew well over a long let, changing a sound lock is money better spent elsewhere. Very often that elsewhere is the door itself. A dropping uPVC or composite door will chew through a brand new cylinder and a new gearbox within the year, and the lock is rarely the thing that was wrong.
What a change actually involves
On most front doors it is a cylinder change rather than a new lock. On a uPVC or composite door the old cylinder comes out and a new one goes in, and the rest of the mechanism stays where it is. On a timber door with a mortice lock it is usually a like-for-like replacement.
While I am there I check that the door still closes properly into the frame and that the handle lifts cleanly, because both of those shorten the life of whatever is fitted next.
The five-minute job that prevents the argument
Whether or not you change the lock, write the keys down. How many exist, how many you issued, and who holds them. Have the tenant sign for them at the start and count them back at the end.
It costs nothing, it takes five minutes, and it settles arguments that otherwise have no answer.
Need a locksmith between tenancies?
I cover Perth & Kinross, Fife, Stirlingshire, Clackmannanshire, Lanarkshire, West Lothian and Dundee & Angus, seven days a week from 7am to 7pm. No call-out fee, and the price is agreed before I travel.
Call or WhatsApp 07890 295 804.
This is general information about how things work in practice, not legal advice. For your own circumstances, check with your solicitor or letting agent.