I was in England 20 years ago and even then, it was a noticeably atheistic society. All the big churches we visited were museums and when we went to services it was apparent the others there were also foreigners.
It’s a mix.
Last time I was there was 2014 for a few weeks.
We attended St Martins in the Fields off Trafalgar Square for several Sundays. And it was pretty full, of actual English people, and there was a group confirmation one Sunday with a lot of City types.
But the statistics show overall church attendance very low.