Lyric discussion by CzechAtheist 

I think that this song is actually about Take That before 1995. They were famous ('standing on the edge of forever'), they were singing all those love songs ('shouting love at the world'), but the public didn't actually realize that they were just an object in the hands of manager(s) and that their life was fully controlled. It was uncomfortable for them, but they didn't really have guts to leave the band ('bleeding, but none of us leaving'), or even say something against the way they were treated because the managers made them believe that they would be nothing without him ('watch your mouth son or you'll find yourself floatin' home'). 'The Flood' seems to symbolize the point when all of these emotions would finally come out of them. In other words, they say that although no one from outside (i.e. their fans) knew, they had to stand those terrible conditions ('learning how to dance the rain'), and trey tried to behave the way it was expected from them ('we were holding back the flood').

However, that's only the first (negative) part of the song. Now, Take That are re-united but without those people controlling their lives ('there was more of them than us, now they'll never dance again'). It also seems that the members are finally happy that the band is heading somewhere ('there's progress now where once was none'). They are no more just one of those boy groups which is a hit in the first year and already forgotten in the second one. They are different now, they are aiming somewhere. (The official video to this song might be as well a metaphor to this; no matter if they win or lose in the competition with other pop groups now, they won't stop. Unlike other groups which only want to be the best.)

Just my own opinion of course. I am not a native English speaker, so I might have misunderstood some of the lines.

@CzechAtheist Brilliant analysis... it is an autobiography of the band's beginnings and how they now have power, when before, they were powerless kids. Robbie, who wrote most of these lyrics, felt especially tramatized, as he was just a kid of 15 when they started. He still holds animosity over being manipulated and pressured by the band's manager Nigel Martin-Smith. It's Gary's lyrics that are more uplifting: "No one dies in these love-drowned eyes" and "There's progress now where there once was none." The two perspectives fit together to create a powerful narrative.

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