Scotland will almost certainly have in their squad Glenn Metcalfe, Shaun Longstaff, Gordon Simpson, Martin Leslie and his brother John, the outstanding centre thus far in the Five Nations. They all originate from New Zealand. Another near-certainty is the prop Matthew Proudfoot. He is from South Africa.
Nor should we forget the Scottish raids across the border. David Hilton is a Bristol butcher who plays for Bath. Paul Burnell is from Reading. Andy Reed was born at St Austell in Cornwall, which is about as far from Scotland as it is possible to go on the mainland. And Budge Pountney was born in the Channel Islands and comes from Hampshire.
Ireland have a similar player in Kevin Maggs, a Bristolian who opted for a green jersey - as Kyran Bracken considered going for at one stage of his career - while Malcolm O'Kelly was born in Chelmsford.
The Irish are, like the Scots, a migratory people. Nonetheless I have doubts about the inclusion in the squad of Ross Nesdale and Andy Ward, from New Zealand, and Dion O'Cuinnegain, from South Africa.
My native land are - always have been - relatively modest cross-border plunderers. Shane Howarth plays for Sale in the English Premiership and was previously capped by New Zealand. The new addition to the Welsh team who bears the fine old Valley name of Brett Sinkinson is uncapped by New Zealand but is as much a product of that country as Anchor butter.
Peter Rodgers, the much-needed loose-head prop, had a father from Trimsaran, near Llanelli; was born in Maidstone, learnt his rugby in South Africa; and plays for London Irish, even though he has not played much this season on account of injury.
England look like going into the competition with an all-English squad. There was a flutter, some weeks ago, about whether Joel Stransky would be added. First Clive Woodward, the England coach, said he would be sad if he had to enter the competition with anyone but a true-born Englishman at outside half; which appeared to rule out Stransky. Then he said he might consider the former South Africa outside half, who was playing for Leicester until his injury.
That injury, combined with his failure to meet the three-year residential qualification by a matter of weeks, seems to mean that Stransky will not be wearing a white jersey. Despite the emergence of Jonny Wilkinson and the on-and-off rehabilitation of Mike Catt, he would fill what is still a gap. It is interesting that Woodward is advancing the claims of Nick Burrows, who learnt his rugby in South Africa and plays for London Irish. He may be needed yet should anything untoward happen to Jeremy Guscott.
On the whole, England are less prone to go on cross-border raids than their neighbours, or to ransack the southern hemisphere for its hidden treasures. It was not always so. In the decade after the war, Oxford University were one of the most formidable teams in the land, on a par with Cardiff and Coventry.
The England selectors regularly chose players from the southern hemisphere for no other reason than that they were Rhodes Scholars at Oxford. Come to that, I am not sure they were all at the university in that capacity: Clive van Ryneveld and Murray Hofmeyr from South Africa, Ian Botting from New Zealand, Basil Travers from Australia. Their selection was, when you come to think about it, a thorough disgrace. And yet, to the best of my recollection, no protest was made at the time.
We are seeing, every evening on our television screens, the malign consequences of an obsession with nationality. Even so, I feel rugby union has become a little too free-and-easy and its ways. I should certainly decree that, once a player had been capped by one country, he could not go on to represent another.
This would disqualify Howarth from representing Wales. It would also prevent the New Zealand selectors from treating Western Somoa as the junior academy of their national side, with players flitting between the islands as if they were ancient Celtic saints hopping across the Irish Sea.