We have a neighbour who smokes weed all the time. They didn't used to, it seems to have started during lockdown. Or they have a new partner who now lives here and smokes. It's not clear. The weed smell comes into and completely fills our flat, and it lingers. It's incredibly strong, enough to give me a headache.
We have young children and the smell fills their rooms, so this has been stressing us out. We have mentioned this to the neighbour a few times, and each time they have said ok I won't do it inside again, but they continue to do so. It's becoming unbearable.
We are reluctant to get the police or some other authority involved (especially because this will need to be declared when we come to sell the flat) but will have to if it doesn't improve. Does anyone have any advice, either on how to get them to take us seriously and stop, or on the legal side of things (which authority to speak to, what the process is, etc.)?
Thank you.