Far under the Guardian's usual level. The specialness the author tries to construct doesn't exist. The church attendance in the UK is one of the higher ones in the EU; for instance higher than in France or Germany. The special thing about the UK is the Anglican church - I don't see how he can make claims about the UK being more secular then the continental countries and keep a straight face.
And while the conservatives in many European countries are Christian Democrats, that is not the case in all of them. For instance the UMP in France is no more Christian than the Tories in the UK - rather a lot less.
There is more official church/state mixing in Europe than in the US, that's true. However that mixing isn't limited to Christianity; any Religion able meet the requirements is able to obtain that status. On a personal level however, Church is far less important than in the US; for example, politicians are not expected to be god-fearing saints. Even Christian Democrats are not expected to be frequent Church goers or fundamental Christians; some are not Christians at all.
The taking over of European politics by fundamentalists is one of the greatest fears Europeans have; the reaction against Buttiglione is a good example for that. Many (left) people look to Italy and are afraid; the embracing of creationism for the schools, the close ties to the Vatican - the mere possibility of the (Christian) Conservatives at home imitating Berlusconi's or Bush's fundamentalism, these things are the stuff of any Social Democrat's nightmares these days.
Here is a better article on the matter:
http://service.spiegel.de/cache/international/0,1518,325722,00.htmlAnd:
http://service.spiegel.de/cache/international/0,1518,326279,00.html