This is an interesting article that fills in some of the blanks - probably from a "lefty" which invalidates his understanding of the law for some of the "let them all drown " brigade but interesting all the same
https://www.freemovement.org.uk/refugees-claim-asylum-upon-arrival-first-safe-country/
It's interesting, but it's a pressure group with a particular point of view. The former Director General of Immigration Enforcement had a very different view. As ever with these things, you can take your choice.