Since his brother died three years ago, lots of young male cats have tried to move in.
They have all left pdq with a resounding earful and helped along by some shrewdly place blows from our cat.
For three weeks now, an intruder has been quietly asked to leave and then chased down the garden. He? She keeps coming back, sits on the garden path and looks hopefully towards the cat-hole and if I am in the kitchen looks hungrily towards the door.
Not falling for that one.
If intruder stays away too long, our cat goes looking for her.
Presume she is female, knowing the treatment the tom cats received, but perhaps our lad is just feeling lonely.
I shall have to find out if anyone owns this little black puss, or not.
Dd has her own cat, who doesn’t want a friend. Next door’s cat kept appearing all over their house, including one morning on an outdoor landing windowsill, about ten feet above the ground. 
To think that London, or anywhere else for that matter, does not belong to any one demographic
