Next door neighbour cat

I recently moved into a new one bedroomed flat. I have two cats of my own, that live inside. One of the neighbours has friendly little ginger and white tabby, with a sore hip, I think. It can't wag its tail properly and it has a limp. It's very friendly and drops by to see me and my cats once or twice a day. I sometimes hear it meowing and it sounds sad. It doesn't hang around for a long time, but it loves a good scratch and a pat. I'm half tempted to take it in, but I imagine the neighbours would object. I'm not feeding the cat or anything. She's a short haired cat, but I can see her nipples, they seem quite pink and kind of large. My two girls are both desexed and I can't see their nipples.. Is the neighbour's cat behaving normally? Could she be pregnant?

I don't know anything about pregnant cats, but I could see why you would think she is cause of the nipples. I'm thinking the same thing. I know some people will let a neighbor kitty visit.. I would strongly recommend talking to the neighbors about their cat's condition - the limp could be a broken leg that healed wrong (I had a foster with this situation.) Ask if they know if she's pregnant at all as well. They might not be aware, or they might reveal she is spayed. Either way, having a friendly conversation with them about her will get you some information and allow you to find out if they care for their pet properly or not. I once rounded up a super skinny cat that appeared on our property one day. I put him in a kennel and was ready to take him to an ER clinic when I decided to see if our new manager, who had just moved in, was the owner. I was able to hail down the son and found out it did belong to them. I asked why the cat was so skinny cause I was suspecting abuse! He explained the cat was like 16 years old and had all sorts of health problems. I later found out from the manager herself that he was in fact on his last leg but she was having a hard time making the decision to part with him because she was so bonded to him... So sometimes there are reasonable explanations for what seems like worrisome care.

I strongly agree that I'd go talk to your neighbors.  I think it would be wrong of you to take in a cat that you know is owned. I'd just go ring their bell and start by politely telling them that their cat comes to visit a few times a day and you're concerned about it's hip and are just wondering if the cat is okay.  Then I'd give them a chance to give you their perspective. Depending on how things go you may then want to go on to mention the potential pregnancy. While it can be frustrating and painful to see people treat their cats with a level of care lower than what we'd give, I do think that ultimately, unless the cat seems to be clearly in danger or actually truly neglected (which I wouldn't say is at all certain just from what you've seen) we need to let people deal with their own cats and make their own choices about them.

Regarding the cat's behavior, for a friendly socialized cat this is normal, yes. I don't see any warning signs from her behavior other than the limp you mention.

Good luck sorting this out with your neighbors and thanks for looking out for this cat.