I open my window a small amount...

[SideWinder]

...and flies always seem to somehow get into my bedroom.

Why is it? So annoying. It is literally less than a foot high and 4 feet across.

WHY.

I am clean,tidy and don't eat in my room.

 

[SideWinder]

It's pretty inexplicable that a fly could fit through that, as described.

Have you missed an important detail? It sounds a bit far fetched otherwise

2 in the past hour...no details missed.

I live in London. Maybe lots and lots of flies...