Well, it's in E minor, tricky to work out though as it's quite a sparse song, mostly Guy singing and drums. I find it easier to work out chords when there's a bassline.
I'm no guitarist but the guitar 'melody' in the chorus goes
F# F# F#
F# G G G G A A A
A G G G G F# F# E
and later they throw some G# (Ab) in there too.
I *think* the whole song goes G major... E minor... G major... E minor... it's not a true E minor though as I can hear a C# in places but no C.
and the bit at 2:20 or so goes
E minor/E minor (possibly B minor)
E minor E minor G major A major
That should be enough to be going on with for now. Forgot how much I love this song!