Writer seems to overlook the issue of the UK no longer being in the EU
You're likely referring to the line "Hopefully this draws a simple line in the sand for the UK government, ..."; the strictest interpretation of the metaphor is certainly muddled, but it is common in the UK to look to EU rulings and policy discussions for comparison to our own - politicians will be aware of them and will use them to help decide whether or not to test things in our own courts.