I'm from the south of USA and we get mosquitos but they don't buzz. They land on u, suck some blood, then leave. and your left with a bad itch. Nothing bad really, its just like getting bit by a flea. BUT they can carry a disease (I've been bit by thousands in my lifetime, no disease yet xD lol) but I don't think it was a mosquito. They are another as big as your fingernail. Search "blood sucker" they are alittle bigger so make noise... I believe.
I heard this droning, high-ish buzzing intermittently for an hour or so; I thought a piece of my tech was malfunctioning. Then I saw it: a flying insect that looked like a smaller, darker crane fly.
Its body is now squashed but from what I saw it definitely bore a superficial resemblance to the mosquito images on Google. The buzzing sound was unlike anything I've heard from a flying insect: monotonous, droning, in-and-out, almost like a crying sound. It wasn't particularly high but it wasn't a low sound.
Could it have been a mosquito? In a UK bedroom in April? Thanks.