Storing flour in the UK

I've been looking at buying some flour in a bigger sack.  I usually buy flour in 3kg bags and have various other small bags of rye etc.  As the 'B-word`' seems to be finally happening, I was going to buy a 10kg sack of white bread flour from Wessex Mills just in case but I'm not sure how to store it?  It's not a massive sack and I tend to make 2 - 3 loaves a weeks.