It's extremely common in South Asian communities (https://www.reddit.com/r/interestingasfuck/comments/10yx3va/...). The UK has a large South Asian diaspora.
I love this site down voting facts if it doesn't conform to preconceived "progressive" notions.
The vedas have many sections which get widely ignored.
Edit: HN throttling is terrible. Here is a link to a couple studies [https://pubmed.ncbi.nlm.nih.gov/32641190/], [https://www.researchgate.net/figure/Trends-in-consanguineous...]
AP has the highest rate, around 28%
But note that the article is really talking about first-degree incest/pedophila/sexual abuse which is taboo in pretty much every society.
In religion, you can find your reasons for anything. e.g. In Mahabharata, Arjuna and Abhimanyu married their cousins.