I don’t understand. Catholic schools in the UK can’t restrict admission to just Catholic students? They have to let at least half of the students be non-Catholic?
I wonder if the madrassas are limited by the same riles
Not exactly.
The UK allows for public funding of some religious schools - these are called 'Faith schools' and (to use terminology familiar to Americans) are a kind of hybrid public/religious school. 'Faith Schools' that already exist are required to offer places to students of other faiths (or of no faith) in cases where they are not full. They can give priority to students of their own faith, but if they still have spaces must offer them to all.
The rules apply to Faith Schools of any type - not just Catholic. In fact, the largest number of Faith Schools are Church of England - Catholic schools are second with much smaller numbers from other groups.
Since 2010, new (not existing) Faith Schools have been required to offer 50% of their places as 'open places' where religion is not considered as part of the entry criteria. This was done as part of a deal to allow an expansion of more government funded 'free schools' - again, to use US terminology, these could be considered as public charter schools. It was basically a compromise to get those free schools into existence. Note - those 50% of 'open places' could still go to students of the school's faith. They were just as entitled to them as anybody else, so in practice, such schools would likely still have more than 50% of their students coming from their core faith.
The Conservative government pledged last year to remove this 50% cap on these newer schools. They are now proceeding with plans to do this and at the moment it is likely to happen - this article is about people who oppose that change, but they are fairly unlikely to succeed.
All of the above only applies to 'Free Schools'. It doesn't apply to any of the other types of schools that exist in the UK - and that's quite a complex mix. Free Schools are only one part of the state system.
And private/independent schools are another thing again.