Lyric discussion by Black&GreenAchilles 

Cover art for Jugband Blues lyrics by Pink Floyd

I agree it is intensely sad because it's his cry for help that his friends totally ignored.

I'm pretty sure it is 'room' - in reference to the imprisoning isolation and seclution the band aboned him too. It's blue because he's still & frozen in time - as oppossed to sea isn't green (growing / alive).

Syd was totally sane, the apparent insanity was a mockery of other people assuming he was mad - it got real with the mis-PRESCRIBED mandrax & his fustration. "The tune they play is an ask confide" - but they never did, they just decided about him. Hence 'I wonder who could be writing this song' is a sarcastic dig directly at the culprits - Floyd (clowns), who loved to tell everyone how mad he was everytime they were promoting a song, 'he's over there but he's not really there. That makes us cool so please buy our hat'.

Floyd was his dream - the backing band took over because they failed 'to get it'. The joke is his mockery of them - him overplaying Carry On style what they had been so ignorant & limited to assume. And then they left him with it, forever. What a great bunk of guys, crying all the way to the bank.

it is not "room" it is MOON .Take a look to the video ,you can see his lips saying moon not room

Not Valid

It is definitely moon, not room. I presume moon is a reference to madness

@Black&GreenAchilles A lot of assumptions here. And it's not "the tune they play is in ask confide", it's "the tune they play is in us confide".