More indicative / venting than any real chance
Looking at the json only about a 100k are not associated with the UK
"name" : "United Kingdom",
"code" : "GB",
"signature_count" : 3549478
I do appreciate that this probably indicates there is a lot of other rubbish in the data. Yes I am sure that the real people who sign the petition would like the country the think again, but are realistic that this won't happen. But they would like the petty inbred retrogrades that appear to run the country that we pretty P***** about their squabbling, one upmanship, and vested interests that have created a whole load of pain for us and the next generation which we don't really need.