How do I get the fecking neighbours cat to stay out of my house? Advice needed as I might strangle the bugger.

[SchrodingersUndeadMew]

I can't lock the door as my cats go in and out and tbh, I don't want to have to lock my door because my neighbour can't keep tabs on their cat.

It comes in the house constantly, eats the other cats food and fights with them (I have 3), it is left out all day and all night and at night when the doors are locked he will climb in the top of the window, I can't even have my bedroom window open at the top at night as he climbs in and I have my 13mo in the same room, he jumps on his bed.

WTF do I do? He's driving me nuts, we will put him out and 5 minutes later he will be back in again. One of my family came in the other day to find him sleeping on his bed.

We are in a cottage flat and it's the upstairs' cat.

I think water is probably the least mean and most effective way to get rid

That doesn't work on him unfortunately. :( I have picked him up a couple of times and put him out but I am scared to do that.

I petted him outside one day and he bit my arm hard enough to break the skin.

When the windows and doors are locked he also comes to the window and taunts my girl cat, she goes frigging mental at him and attacks the window, I'm losing my sanity here.