Nope, you don't need it. If for any reason there is a problem and you can't feed your baby for some reason, all UK hospitals do have formula. They won't offer it to you if you are simply choosing not to BF, but if you are medically advised to top up BF with formula as a supplement (btw, I'd strongly recommend NOT doing this unless it's an absolute emergency), they will supply ready-made formula it in small quantities. My daughter wouldn't latch for 6 days and I had a hard time hand expressing/with milk coming in, so was advised to supplement with formula for about 48 hours because my daughter was losing weight (wish I hadn't but that's another story). They all but forced it down her throat (and this was at a UNICEF 'baby-friendly' hospital). More than likely you won't need it at all! And even if you did and you wanted to use your own, you can always send your partner out to a 24 hour Tesco for some ready-made formula (they even have it in pre-sterilised disposable bottles for use at the hospital). There's no reason to stock up on something you don't want to use and very likely won't need anyway.