Lyric discussion by Josabeech 

There is a YouTube video of the band performing this at Bristol Academy and in the description of the video, the user goes to talk about how he and his friend think the song is about drug addiction. I'll just copy and paste what he said...

Just thought I'd throw this in:

I was discussing this song with my friend and his response absolutely blew me away. He said it was about being addicted to drugs but then he fell in love and she keeps him from going back to drug use. Prepare to be amazed:

Blue light is installed in public toilets in seedy areas so that drug addicts can't see their veins. Verse one relates to addiction, and the "shadows" and "cupboards" being the dark places in the mind where the addiction grows and is found. "It will...every night" relates to the feeling of invincibility that some drugs can give you; ditto for "It will...remember" and the feeling of clarity.

Verse two is about a lover no longer at hand; "What could I ever run to?" is the narrator's pathetic plea that drugs were the only possible substitute for the love he has lost. Lines three and four are ambiguous; either, as conventionally assumed, they are about the lovers having been parted and as such being torn apart and unable to sleep; or the lover is also addicted and the drugs are wrenching her body apart and stopping her from sleeping.

"And you didn't even notice..." is about beautiful moments of love that were numbed by drug use. The "And you couldn't tell..." line is often misinterpreted; rather than saying that the lover couldn't tell the difference between them, the narrator in fact refers to an event (that she "didn't even notice") of the-sky-turning-blue-and-one-not-being-a ble-to-tell-the-difference-between-them (I hope this is clear).

The final repeated line ("You are the bluest light") is a sober realisation that her love is the only thing that will stop his addiction. She acts as the blue light hiding his veins from view; the light that prevents him from reentering the dark "shadows" and "cupboards" of his mind.

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