We moved to a new house back in July, with our adored cat Polly, who is a very slight little thing, incredibly affectionate but nervy. She coped with the move ok - kept her in for 4 weeks, then got a cat flap installed. Almost immediately we had a problem with another cat coming in, walking right through the utility into the kitchen where it would scoff all her food. She is terrified of it, and it's not surprising considering it is a very bedraggled and scruffy Maine Coon - and absolutely enormous. A neighbour says it has been living rough for ages, almost certainly abandoned by someone. Such a shame, as it's an amazing cat, but a real nightmare for us.

I've tried to catch it in the house. Polly will start yowling upstairs in the night, but by the time I'm out of bed and out the room, the cat flap bangs and it's off like a rocket. I've tried sleeping downstairs on the couch 3 times. I set the flap to "in but not out", and on the last occasion it came in and woke me up in the process. I jumped up, it ran from the kitchen and simply smashed through the locked flap, leaving it in two! No cat flap would keep it out as it's so huge and powerful. We've started to shut Polly in at night (much to her annoyance), and blocked the flap with a big heavy toolbox. Last night, 2am, she woke us up making the most incredible noise I've ever heard. We shot downstairs to see her atop the tool box, with the Maine Coon bashing its way in. She was going mental at it, but it takes no notice whatsoever. As soon as we appeared it shot off up the garden.

It is driving us crazy and I have run out of ideas. Any flashes of genius would be much appreciated.

If its abandoned then get on to Cats Protection or other local cat charity. They should be able to assist in catching him and re-homing.
I use a chip recognising cat-flap - though a cat like your maine coon would probably bash its way in - generally its quite good at keeping other cats out.

As Shrike said, but also, try not leaving any food about overnight. Polly will soon adjust, and it might just solve the problem, but it might take a while.

Thanks for that. I will contact them right away!

Problem is that it also comes in during the day sometimes. It's been in when we've been at home at the weekend, and when we're at work (can tell as all the food is gone, and Polly's behaviour is a giveaway).

Cats Protection not a lot of help (no branch in our area), and seems RSPCA only have one person working in East London - left a message on her phone so I will see if she responds. Also spoke to a cat charity that aren't all that far away, and they said they will get back to me. I might try the council, but I doubt they'll be any help. Seems crazy that they will deal with stray dogs, but not a cat that is the size of a dog!!

Obviously I don't know whereabouts in East London you are and if they cover that area, but I've generally heard good things about these people, might be worth a phone call http://www.woodgreen.org.uk/

Got to Cats.org.uk to find your nearest Cats Protection centre - it may well be Central or North London, maybe Greenwich or Basildon depending where in London you are.
For local charities look on catchat.org
Maybe Battersea Dogs and Cats home covers your area?
Main Coons don't do well living on their own - I'd be concerned about his welfare more than the fact he is nicking food!
Mind you be careful when you do talk to charities - if they get the idea you are feeding him they won't consider him a priority.

I'll come and kidnap him. I've been MaineCoon-less for 18 months and a house is not a home without an MC. Or two.

MC's are perfectly capable of destroying the average catflap. We got through 4 spare doors during the lifetime of our two and a previous MC actually strolled off down the drive wearing the frame over his head after he'd decided he was going out and a locked catflap wasn't going to stop him. For this reason, a catflap that is microchip or magnet operated won't necessarily keep him out. And the previous occupants of your house may have been feeding him anyway.

I would also suggest CPL so if there's no active branch in your area, that's a problem. If he has been abandoned MCs are often too large to successfully get by on a diet of rodents and aren't sufficiently agile to catch birds so he may be very hungry.

oh dear!

poor Polly

I was going to suggest a micro chipped cat flap but seeing as the cat is huge it might not work

dont leave food out is the only thing I can suggest but I see you are already doing that

possibly lock the cat flap during the day for a while - Polly wont like it one little bit but it might discourage the other cat from coming in

you COULD leave food outside for the maine coon cat - not really advisable but it its just hungry (and abandoned through no fault of its own) if you start to feed it and you can gain its trust you MIGHT be able to eventually catch the cat and get it taken to a re-homing center and he/she will be looked after and hopefully re-homed

Thanks guys. I've left a message on the RSPCA voicemail, and these people say they will get their rescue guy to call me:

http://www.celiahammond.org/index.php/contact-us

I'll see if either respond. If not, I will try Wood Green, as they're not a million miles away. Seems to be a dearth of rescue organisations in East London.

I'd love to see the cat be rescued as it must have a miserable time of it. I think it could be coaxed with food - though it flies out of the house when it hears us, it lingers in the garden until we chase it off. Cleaned up, fed and fussed it would make a stunning pet. If we didn't have Polly, I would try to befriend it myself.