I'm a size 14 and really, really struggle with finding decent trousers that don't feel like I'm being sawn in half and I can actually bend in.
So I ordered these from H&M in a medium, not expecting much and they're superb. They're comfy, don't cling in all the wrong places and look brilliant with a stripe jersey.
m2.hm.com/m/en_gb/productpage.0404850005.html#Dark blue
Not sure how they'll wash but I've picked up some lovely stuff from H&M recently.