There's not much out there on this other than a few messy tweets and blog posts and
a letter published by The National but there are plans for "Freeports, Freeport customs sites and Freeport tax sites," on gov.uk which seem to line up with what people are saying and it wouldn't at all surprise me if that's what the Tories had in mind.
This collection brings together a list of Freeport maps, Freeport customs site and Freeport tax site locations legislated for within them, and a statement on the designation process.
www.gov.uk
Think someone may have posted about this in one of the crypto threads, but there was one set up in Honduras that didn't go too well.
The battle over land rights and sovereignty on the island of Roatán has galvanized the whole country
www.theguardian.com