This pattern is by Morris & Sons and is availible as a free
Ravelry download. I'm pretty sure you need to have a Ravelry account to access it but if you don't have one - get one! It's free and you don't get sent any junk. Just access to oodles of free knitting and crochet patterns.
I've knitted it in Pegasus Dishcloth Cotton with 4mm needles. I believe it took me just under four balls to make a square blanket. It's been a lovely blanket, nice and soft but hard wearing and 100% cotton for a low price. This yarn is great to knit with, I've done a few projects with it but this was my first blanket. It's really easy to knit with and I highly recommend it for beginners. I used to have a lot (and I really do mean a lot) of blind customers who used this yarn to make dishcloths and blankets for charity. It's ideal because it doesn't split, it's really easy not just to see what's happening with your stitches but to feel it too.