Debenhams always have a good range, get one with the elasticated support thing inside as it really holds u in. Hope that makes sense, I dont really know how else to describe it!
I've worn Spanx with tummy control in the past and I found them pretty good. They can be pricey but you can get them on ebay cheaper and they also sometimes have them in places like TJ Hughes (where I got mine from). I've also worn Primark's own brand which personally I don't find work as good as Spanx but do the job and are cheaper.