With thanks to the Snail of Happiness for this very good idea, I have made a pack-away crochet bag:
The pattern is called ‘String bag pattern’ and the link for it is here:
I used Sirdar simply recycled dk, which is an acrylic/cotton mix, and a 5mm hook. The colour is called ‘pollen’ and it bears a slightly unfortunate resemblance to a burger bun when folded up (perhaps I could develop this as a theme!)
It does however open to form quite a spacious bag….