I've been having trouble with flies in my flat recently and its driving me insane. I live on the top floor of a converted victorian and its a very warm flat. So in summer I need to keep the windows open. However as soon as I do swarms of flies come straight in and staying for ages! Im scared to leave food unguarded for 30 seconds while I go for a ****! Is there anything I could do to deter / kill them? I'm not overly keen on them sticky things that hang from the roof as I dont want a big strip of dead flies hanging from my roof. Fly spray is pointless as I want to actually be in the living room most of the day! Any ideas? The flat is clean. Don't have any rotting animal carcasses or anything bringing them in! They are just doing it to try and **** me off, and succeeding!