They are obviously New England Patriot slippers. They appear official as they have the NFL hologram and were sold by FOCO UK
I would like to know more about the year they were sold and any other info. Google searches, reverse image searches yielded no match unfortunately.
I guess the best I can say is that they’re made after 2008 and not before, because that’s when the NFL logo changed.
I also think the team itself switched from a cursive to a more block-like font more recently than that but I can’t put a finger on when the font changed exactly.
The new Patriots logo font appears to first appear around Oct 2013, going by the archive of their Pro Shop website.
Thanks to you and the sibling comment here. Timeline helps narrow things down. Not being much of a sports fan I had no idea about the logo changes.