Not at all surprised. Honestly, the only reason why Catholic and Muslim numbers are remaining stable or increasing is almost entirely due to immigration, since in England almost half of the population now doesn't affiliate themselves with a religion. I'd not be surprised if a lot of the next generations of both faiths are experiencing a major drop off too.
And when you think about it, why wouldn't they?
Churches haven't exactly been paragons of virtue in the last century or so. Scandals with priests, involvement in politics, the endless changing views of priests, and the equal capacity for church goers to be as abhorrent an asshole as the rest of us dulls the shine of it quite a bit.
Take the USA. The pretzels that people weave themselves into to support the Pope and retain their political values is truly impressive, and you can only make one of those so tight. The reactions and responses from some Republicans to the Pope's proclamations are kind of telling as to what is more important for even "ardent" church goers. How many people are their religion first and their politics second? Is it more important to be Catholic, or a Republican? If we have a liberal Pope, how often will conservatives decide that their politics are more important? When we have a conservative pope, how many liberals? It feels more and more like religion is something even the religious prefer to pay lip service too, and that their beliefs define what their religion is far more than their religion defines their beliefs. How many people are "Christians" and how many are "Cafeteria Christians?" Given how much the faith has changed in 100 years, from interracial marriage back through the treatment of women, and how little of it we actually follow, even the most fanatical of Churches, does anyone actual exist as anything but a Cafeteria Christian?
The CoE is intrinsically tied into politics in the UK. They have seats in the House of Lords and a significant amount of sway through the Archbishop. Whenever someone disagrees with what the religion has to say, it causes some minor crisis of faith. You can only have so many of those before you have to make a decision on whether or not you become closer to your religious body or make your faith your own. When the Archbishop was arguing against women taking on a bigger role in the church, and was doing so inside a political body with real political power, it doesn't make the church more appealing to women, as an example. Fighting against birth control, better maternal care, the NHS, or abortion doesn't help when the majority of people within a country support them.
And a lot of the time, it doesn't feel like the Church is on the right side any more. How often was charitable giving by your Church given to a body you support? How often was it instead waffled away on political purposes? With growing acceptance for women's rights, the church lost some of it's lustre and it has to tone down it's rhetoric or begin losing women. Religious arguments against miscegenation were widespread. A distaste for abortion, and then stem cell research. "Faith healing" that rejects medical science. Now the wide-spread acceptance of homosexuality, with the chief (and these days pretty much only) argument against it being on religious ground. For older folks, how many of these can you go through before you reject the Church? When the Church begins to lose the moral argument and is supposed to be the centre of morality, and people lean towards the morals against the Church, it does the Church no favours. For us younger folks, in their twenties and thirties, it's a lot easier not to get involved in the Church when you see these kind of failures early on before you've spent your life being involved.
Personally, I didn't get involved purely because of assholes. As a kid, the man preaching at the front was highly disliked by my very devout mother, because he never discussed anything in positive terms. It was never love thy neighbour, it was always how we could become damned. There was a little too much "hallelujah" for her, and the sanctimony of it, as if someone else could be more closer to God than one of his creations, pissed her off. So we didn't go back after a few weeks. As much as people say we've lost some sort of morality, I'd say I'd disagree. I think the only thing we've lost is the ironclad structure that it was in, and I'm not sure that was a great thing. I was raised with the same lessons as all the other kids and I've lived a fairly good life. Compared to the hippies of years past, our generation isn't in horrible shape. And I've done it without sharing anything in common with the Westboro Baptist Church, without having to listen to my fellows of the faith shit on women, or on gays, or on whatever politician they happen to dislike that given day.
I don't think the Church serves as that moral arbiter for a lot of reasons. Mainly, because so much more of our population lives in places where the Church isn't a major part of life. In the country, the community centre often is the Church, and a lot happens there. The various groups associated with it run a lot of the community events. In the city, though, there are a lot of alternatives to the Church. My Scout group was one of the few originally not associated with a Church, but now a lot more are. We still developed our morals, but did not without Church doctrine. I don't buy that it's changed anything. Hell, I bet people would be hard pressed to find evidence that the irreligious differ in a negative way from the religious in terms of morality, whether it be incarceration rates, drug use, pregnancy, or what have you.
Finally, I don't buy that this is the end of a belief in God or his doctrines. I think it's simply the rejection of having other people speak of your beliefs in your name. While the amount of people leaving Churches is at an all time high, the amount of atheists and agnostics out there hasn't increased overly much. If anything, it seems a lot of people are willing to belief in a God, they just don't like the environment they were forced into so they can believe in that God. If that's the problem, then the issue isn't a growing lack of belief, or a growing loss of morality, it's a failure of the Church to allow faith the grow as it should.
At the end of the day, with attendance falling in most Western countries, I simply personally believe there is an part of the Church that is somewhat antithetical to the freedoms we enjoy in modern society. Churchs inherently require some sway over how people think and what they belief. The capacity to engage in discourse, the way we develop our thoughts, or willingness or choice with who and when we engage with others, are all things we must in part curtail if we want to support a Church, and for many that is no longer acceptable. The inherent value of freedom comes from the idea that men or women can make generally correct decisions if they are independent from the Church. When the Church makes a mistake, people are more willing than ever to recognize it, and question the hierarchy as a result. The longer it takes the Church to change, the faster some leave. The faster Churches change away from old doctrines, the faster the old guard leaves. People are free to give up some of that freedom (they ironically have freedom to do so), but that kind of societal freedom does impact the way we think. I feel it's make us more individualist, and I don't think it's a bad thing that people now think more for themselves. Either way, I doubt we will see Church attendance rising in anything but where the radicals go -- towards fundamentalism (if the CoE isn't enough, I'm going Baptist), or towards extremism (as with cults past, so too with radical religious sects going forward). I think, however, that will only shore up numbers for so long, before
they start declining too.
I'm not saying the loss of Churches is a good thing. I definitely don't think the rise of some of the replacement belief systems has been a boon for Canada. But I can see why Churches are in decline.
Just my thoughts.