advice re invading cats?

[deeplybaffled]

Hi

we've recently started having problems with a neighbour's cat breaking in through the cat flap.
We've got 2 cats, both female and neutered, and the invader is female too, not sure about the neutered bit.
a few weeks ago, I heard the cat flap opening at high speed - it's one of the magnetic ones - and then my older cat came flying upstairs, followed by the invader, who ran off when she saw me. when I went downstairs, the cat flap door was ripped off its hinges!
we mended it and all was well until this morning, when I came downstairs to find my two cats and the invader in the lounge and the cat flap broken again, this time with the magnet bit cracked! Sadly, as it looked ok, I didn't realise and DH came home to cat poo everywhere, so we think she came back yet again, whilst we were at work, and either soiled the house herself to stake territory or upset our cat enough that she did it in fear:(
So we've mended it again, but the invader is clearly pretty persistent, and I think she'll be back...
my kitten isn't bothered, but the older cat - who is only 2 and bigger than the invader - is obviously unhappy.
Any tips on how to deter the invader? I have water pistols loaded, but she comes in when I'm asleep or out, so that's not helping. And both my cats love going out, day and night, so locking the cat flap wouldn't be popular either.
so can anyone think of any deterrents? A microchip flap might be an idea, or is there anything else we could try?
thanks, all!

[cozietoesie]

Microchip cat flap - Sureflap is th one most posters use and is apparently very robust. Just under £70 online.

[deeplybaffled]

Do you know if they can be moved? We are hoping to move house in the next year or so, so if we could take it with us, it would be a financial help!

[cozietoesie]

Don't see why not - although you'd have to put something in/repair the consequent hole.

[steppemum]

we have a microchip flat, was worth every penny.

But, if he is chasing your cat in through the flap, he may be able to do that even through the microchip flap, in the second before it relocks.

We had this (which is why we got the microchip) and I set the flap on in only and caught the intruder and dunked him in buckets of water, and it didn't deter him at all.

yes you can move them, they fit into same space as a normal flap.

[cozietoesie]

You might get a 'hot pursuit' incident I guess but I reckon those would likely be in a very small minority. All the pursuing cat has to experience is one dunted head and they'd be appropriately cautious on following occasions, hopefully giving the mechanism time to lock.

[deeplybaffled]

Thanks- it's that split second that worries me as the invader is obviously very persistent! Is there anything else I could try that might repel the little pest? Considering signing big cat up for karate classes or something at this rate to get her to scare off the invader...

[cozietoesie]

The old 'constant vigilance' allied with a water gun - at the beginning. You'll be keeping your girls in at night I assume (night being the most dangerous time for them) so standing in wait after rattling food bowls of an early evening is a fair idea.

I would hope the combination of all factors would teach the invader a thing or two in fairly short order.

[MissFoodie]

ditto sureflap, best thing ever
dont bother with pet porte, my intruder could still break in!