Can't get spy out of city

[Skoran]

I recently started playing med 2 with scotland, I conquered england and got a foothold in Europe when I captured caen. Needless to say caen is beign besieged almost every turn.
But every fight I hear a voice say that some snake has opened the gates. Ok, can happen but after 25 sieges it gets boring, I wanna place my men on the walls like I want too, not make em run around till they are all positioned.
I don't only have this problem in caen but also in antwerp. I already trained a spy in these settlements but it doesn't help.
Is there any way of getting that annoying spy out of there so I can prepare my troops before they attack?

[khaos83_2000]

There's only one way.
Get 1 or more spy in ur city. high level spy if possible. General with traits, % increase in detecting spies, also helps.

[Ramses II CP]

Build watchtowers in the area so you can see the enemy spies coming, and set your assassins on them before they make it in.

[phonicsmonkey]

when you have a rat in the house sometimes you need more than one rat catcher

just keep putting more and more of your own spies into the settlement until they flush out the rat

say to them "There is no need to remind you that if you don't find that cheese eating rat b*stard in your department... it won't be me who suffers for it."

if he escapes, send the hit squad after him

[ReiseReise]

Try to find a general who has +public security traits. If you catch a spy the general in that town usually gets a trait. Otherwise just keep pumping out spies of your own. Try to have at least 4 in your problem city. They will increase the chance each turn that the spy will get caught if he is already in the city, and will make it harder for him to return.