To ask when a guest becomes a lodger?

[PicaK]

Offered to put a mate up for a few weeks/month whilst they find a new house.
At what point are they a lodger? Ie for council tax (I get single person discount), insurance, tax purposes etc

Don't want to break the law.
Not really an aibu sorry - posting for traffic and advice

Are they paying you or staying for free as a guest would?

At the point where they pay for board.

For council tax purposes, if they’re living with you & have no other residence, it doesn’t matter if they pay you or not. You’re no longer living alone.

For council tax purposes you are no longer entitled to single person discount because your guest isn't currently paying council tax elsewhere. IME of friends who were between permanent homes once they told their old council that they were moving out and no longer paying council tax there was definitely some sort of check up that they were paying somewhere else. There might be a time limit on how long they can stay and still be a guest but I doubt it it's as long as a month.

Why not ring the council and ask?