I have no means of being scientific about this, obviously, so here is my anecdotal response.
I have seen lots of people use a baby carrier of the Baby Bjorn/Tomy variety for the first couple of months. You can buy them on the High Street - it is a pretty mainstream thing to do. Obviously, the baby quickly becomes too heavy to be comfortable to carry in this way, but more and more babies at least have the security of being carried in their earliest weeks. I think it is partly because our town centres are mostly pedestrianised, and they are often also medieval. Cobbled streets and tiny-baby-in-pram is not a happy mixture for a Saturday shopping trip.
Most people then move straight on into prams and buggies, IME, except for when they are going on long walks, and then Karrimor-type backpacks are common, at least among the middle classes.
But there is a little move towards baby/toddler wearing, again, among the middle classes. One clear indication of this is the NCT catalogue - the National Childbirth Trust is the nation's big natural childbirth charity; they organise antenatal classes and have active networks of local branches with coffee mornings, tea parties, nearly new sales etc etc. And as you can see in the NCT catalogue, there are various baby carrying devices advertised. I think there are more than there were 2 or 3 years ago, but I might be misremembering.
1. The Wilkinet. What a splendid invention this thing is. It starts like a standard baby bjorn type baby carrier, but as the baby gets larger, they can face outwards or can be carried on an adult's back, rucksack style. I have seen successful (though fairly contorted) breastfeeding going on in it with older babies. And the weight really is distributed well. I have also seen fathers very happy and comfortable with a Wilkinet - it doesn't look too earth mother-y for a man with a manly outlook.
2. The better baby sling. I've got a friend with this one (and actually, both parents use it completely interchangeably - an effect of the tartan pattern rather than being a bit floral, maybe?!). It always looked a bit stiffer to me than my faithful Huggababy, but it's a perfectly good ring sling and LOOK there it is out in the mainstream.
3. The Hippychick hipseat. There is one good thing about this. It acknowledges that a) carrying a child unaided on your hip leads to problems and b) every mother carries her child on her hip. But really, how many people are going to wander around the house with this contraption strapped to them for every time a child might want a carry? A ring sling gives you the same load spreading, but is much easier either to whip on instantaneously or leave on all day, wookie-like.
4. The Bush Baby cocoon and baby carrier - the sorts of things I mentioned above. I haven't tried this brand.
I rarely see mothers with slings - local ones I tend to get to know! - but people often say supportive things, and I wave the logo of my sling at anyone who says anything friendly.
There is a growing market on Ebay.co.uk of second-hand slings and also WAHM ring slings. Every time I go to visit, there are more slings on offer and less chance of a bargain!