Someone must be.
He will eat most of the biscuits (measured portion) we give him in the morning but always leaves some. He gets wet food in the evening alongside the left over biscuits. Usually licks the jelly off and eats about 1/3 of the meat then finishes the biscuits.
He does hunt. Brings in about 1 mouse a week but I'm sure he has a couple more as outside snacks.
He is a big cat. Over the 3 years we've had him his weight has always been between 4.75kg-5.25kg. Vet says his fighting weight should be around 5kg so we've been doing pretty well!
Just came back from vet following booster jabs. He is 6.25kg 


He's very well known in our close so I know it's not one of our immediate neighbours. Other than that, he likes to hang around the allotments. I suspect that's where his supply of mice comes from. Someone must be giving him extra food or lots of treats for him to have got so heavy, right?
I've put a paper "do not feed me" collar on him but he's come back in twice without it now. Reducing his food at home means increasing the risk of him just adopting a new family who feed him fucking dreamies
Could I logistically strap a go-pro onto the cat to find out where he goes and why he's got so fat?!
(He hasn't actually got very fat, which is why I didn't notice the weight gain so much. He's just become very heavy!)