It's a secular country that observes christian ceremonies.
You'll find more people at B&Q, Ikea or the Shopping Centre on a Sunday than you will in Church and Christmas is celebrated not by a modest and solemn reflection of the birth of Jesus Christ in Church, but by...more shopping and partying.
Christianity in this country used to be a unifier. I grew up, child of second generation immigrants, going to a school that had a great influx of immigrant children. We sang hymns every morning, regardless of where you came from. I still remember singing the Lord of the Dance, and Morning Has Broken and Together We Learn To Read And Write (can't remember what that was called) etc and our headmaster prayed with us. But somewhere, someone thought all that wasn't politick, and decided that we would all be indoctrinated in post modernist rhetoric each assembly instead. Concentrate not on all being children in christ, but on being individuals and celebrating our differences became the overarching thing. Not that we didn't learn about other traditions etc., but the feeling was they were secondary to the country's prevailing tradition in focus.
Now white indigenous people hardly attend church and ironically it is the immigrants from majority christian countries attending and keeping the traditional churches going in many areas, because they still take Christianity seriously. Immigrants with other religions and from countries where having children is more likely to be perceived as aspirational, tend to practice their faith more sincerely, and have more children so their faith grows in influence. Again, very ironically, Muslims will show respect for Jesus at least as a prophet ,and will spend time talking about that. So will Hindus to a degree. But strangely it is taboo to talk about Jesus to native white British people lol!
The State Church meanwhile groans under the temple of secular postmodernist woke think. The impression then is that non-indigenous faith groups like muslims are 'taking over our Christian country' and it only takes one person doing something stupid, like trying to please everyone by removing some traditionally perceived Christian tradition, for people to get upset and start seeing each new mosque as 'threatening' instead of people saying 'Where is our Christian tradition?'. You can bet your life most people complaining about mosques and immigrants never, or hardly ever, attend church and have maybe two kids max.
It all leads to where we are. Policy, social change, secularism.