I posted this at another blog, and indeed, there are 'Irish Travellers' in the UK. They are considered an ethnic group by the EU, so they get generous state benefits, and they engage in scams and fraud similar to what their US Traveller cousins engage in.
They don't associate with 'country' people, and intermarriage out of the group is almost unheard of.
The largest Traveller settlement in the US is in
Murphy Village, SCIt sounds like some serious imbreeding goes on.
According to Pete Caroll, “marriages are contracted by the parents when the children are mature. The young couple is consulted before the final decisions are reached, and the arrangements are ordinarily made two or three years before the wedding is to take place.” The parents inevitably choose spouses for their children from among the Travelers, using such unions to solidify familial friendships and business arrangements. “There are no captives out there,” Pete Caroll continued. “They are allowed to marry outside the Village if they choose.” They never so choose, of course, for, in addition to the pressure from relatives and peers, they know that the culture of the Travelers is far too inimicable to that of the dominant society for marriage with a non-Traveler to be successful. The extent of intracommunity marriage is emphasized by the fact that among the more than 1,500 Travelers in Murphy Village there are only eleven surnames.