Look carefully you can see the black neutral chilling out in the back of the box

When electricity is used the electrical terminals warm up and subsequently cool down.  Over time this heat cycle can lossen the screws.  If you look carefully you can see the black neutral chilling out in the back of the box.  Get an Inspection and Test (EICR), done every 10 years to stop this happening.  If you are a Landlord every 5 years or change of tenancy.