When you fill in a proposal form for property insurance you will almost certainly be asked about the locks. It is easy to assume that your property, whether it be your own home or an unoccupied one has suitable locks on all the doors or windows. If you are insuring your own house as an owner occupier it is easy to check but this is not the case with a let or unoccupied property that might be miles away. The worst thing you can do is assume that the security precautions comply with your insurers’ requirement- there is no alternative to checking them yourself or asking someone else to do it for you. You will find variances of security required for home insurance, unoccupied property insurance and landlord insurance
Most insurers will require five lever mortice locks conforming to BS 3621 and there may be special rules about patio doors so check your policy. If you fail to comply with the standards set in your policy you may find your claim turned down. It may make sense to change the locks periodically; especially if you know that several people have been given keys but you can only account for a few of them.