In the most famous meeting between Arsenal and Tottenham, when Bertie Mee's team beat Bill Nicholson's at White Hart Lane to complete the first part of their 1971 Double, the "foreign" element involved in the match comprised a handful of Scots, the Northern Ireland goalkeeper Pat Jennings and Joe Kinnear, an Irish international brought up in Watford. Both managers, needless to say, were of solid British stock.
For this afternoon's 171st encounter, there might be up to eight Englishmen on the pitch at any one time which, as our table shows, is higher than in many recent meetings. Yet similar research into any derby in the Premier League would reveal a clear trend: not only is the number of local lads diminishing but so is the number of Englishmen taking part.
Of more than 100 new signings made by Premier League clubs so far this summer, less than a quarter have been qualified for England. Sunderland and Newcastle, Liverpool and Everton, the two Manchester clubs, Chelsea and Fulham, as well as Arsenal and Spurs, have all bought foreign in a trend of deep concern to the England manager Roy Hodgson.
Spurs' transfer dealings have illustrated a dramatic shift away from the policy of recruiting young English players that David Pleat was particularly keen to introduce in his time as director of football.
It seemed to be briefly back in favour when Harry Redknapp signed the Sheffield United players Kyle Walker and Kyle Naughton, as well as personal favourites Jermain Defoe and Peter Crouch.
But this summer's dealings have been stark: gone, either permanently or on loan, are Steven Caulker, Scott Parker, Tom Huddlestone and Jake Livermore, four England internationals who made 70 League appearances between them last season (which would have been far more but for Parker's long injury). In their place have come half a dozen foreigners, at vast expense made possible by Gareth Bale's imminent sale.
Andre Villas-Boas defended the strategy before today's game with a familiar argument about prices. "If there was a player in England with the same level, which there are, then it's perfect," he said. "The problem is the valuation practices in England are impossible to be met for the domestic market. Last year we saw a lot of examples that showed it that way. We did business abroad but we could have done it over here. The most important thing for us is to strengthen our side.
"You could make a study on British players involved in domestic record transfers. I can recall [Steven] Fletcher last year from Wolves to Sunderland; from a team that was relegated to a Premier League team. That was for about £10 million. I also remember [Matt] Jarvis, another one, for £12m. These are very, very big amounts."
So, some might argue, are the sums spent on Erik Lamela, Roberto Soldado, Paulinho and the rest. It is not Villas-Boas's job to help the England team, of course. The net effect, however, is of English players at clubs like Tottenham being forced out by foreign imports, almost always to places where they will not be experiencing any European football.
Alternatively, as with promising young talent like Tom Carroll and Harry Kane, they stay but are then restricted to cup games and an occasional substitute's appearance.
Both did well in the dead Europa League tie against Dinamo Tblisi on Thursday night but may yet leave on loan before the transfer window closes tomorrow night.
Hodgson said: "Their path is blocked by extremely talented players. I've worked at Fulham and West Bromwich Albion, and Tom Carroll would probably have played in both of those sides. But he doesn't play for Tottenham. Is that their fault? No, not really. Maybe he's not quite as good as Dembélé, Sandro or Paulinho."
Hodgson praised Spurs, Everton and Liverpool for giving opportunities to youngsters like Andros Townsend, Ross Barkley and Raheem Sterling respectively, but the competition to those players has risen in this transfer window: the three clubs have signed more than 15 foreign players between them.
Because of the top clubs' desire to have two accomplished players for every position, it can even be other English players who hold them back. Hodgson cited Ryan Bertrand being kept out of the Chelsea team by Ashley Cole. He could have mentioned Martin Kelly at Liverpool and might have asked how many games Townsend will be given once Aaron Lennon is fit.
"I'm not criticising the judgement of the coaches," he said. "These players are too good to let go but they are finding it hard to get games. As a nation, we must hope that their lack of games will not destroy their careers, because it could happen.
''Chelsea, like me, think that Bertrand is a very good player and want to keep him. But it's tough for his international career because I can't really pick him [for England] when he's not really featuring in a game unless it's the Capital One Cup and it's basically Chelsea reserves."
Meanwhile, it will be a small irony if Arsenal, heavily criticised for not spending more money, beat a new Tottenham side still not used to playing together.
Arsenal v Tottenham Hotspur is on Sky Sports 1 today, kick-off 4pm