morale dilema do I keep this cat?

Hey I'm new to this site I just really needed some advice
   
I work at a hospital and for the last 2 weeks a cat has been staying in our garden - it is skinny and has matted fur
   
I decided to take it home with me on friday and take it to the vet to see if it had been chipped
   
It was chipped - I spoke to the owner and he didn't say thank you, it seemed more of an inconvience for him that I had collected the cat and taken it to the vets. He said he only sees the cat every couple of weeks as his other cat does not get on with it.
   
I offered to keep it but he said no its alright I just see it every now and again. I said would bring it back to the hospital and asked him if he could pick the cat up - again this seemed like an inconvience
   
In the end I phoned him back and asked him if he would just like me to release it back into the hospital grounds - which he said would be fine
   
I've had this lovely cat at home all weekend and it's settled in realy well with my other cat and my partner wants to keep it
   
I don't know what to do?? Do I keep it here and give it a loving home - or give it back where it only sees it's owner every few weeks and is scavenging for food inbetween?
   
Ahh tricky one please give me your opinions and advice
   
Many thanks
   
Becky
   
x

I've noticed a few of you have read my msg please leave your responses xx

Keep the cat. Take it home, now. Get it the right care & treatment. The owner obviously doesn't care worth a damn.
   
Call him. Tell him that you want his cat. Tell him whatever it takes to get him to agree - though I doubt he'll object. (Why the hell did he get the cat chipped if he doesn't care about it????)
   
Try to get him to give you a written release so that you can get the registration of the chip transferred to you.
   
I couldn't leave the poor thing out there in the world all alone.