So it wasn't just my browser or my internet connection. I used CTRL + F5 in FF and it always worked, but on a normal refresh it would either display an error or the page didn't load at all.
Thought that my IP had landed on some list where Twitter degraded the connection and I wasn't even logged in.
Yeah, I got loads of these - this tweet is not available to you etc.
Recently, it appears that I can't load twitter URLs with query parameters - the Guardian use some really weird ones of these, but when i delete them the URL loads. Super weird.
Thought that my IP had landed on some list where Twitter degraded the connection and I wasn't even logged in.