The demographic forecasts contained in a new report from Eurostat, the European Union’s statistical agency, are worth a good look. Everyone knows the EU’s rapidly ageing population and shrinking workforce are making its task of promoting prosperity and job growth ever more difficult. But we don’t often see the hard numbers behind the general trend.

What I found most striking were the predictions for the big EU-6. In terms of their current populations, these are Germany (82.2m people), France (61.9m), the UK (61.3m), Italy (59.5m), Spain (45.3m) and Poland (38.1m).

By 2060, the order will have dramatically changed. In first place, says Eurostat, will be the UK (76.7m people), followed by France (71.8m), Germany (70.8m), Italy (59.4m), Spain (51.9m) and Poland (31.1m).

In other words, Germany and Poland are forecast to suffer catastrophic population falls of 13.9 per cent and 18.3 per cent respectively over the next 50 years. From being the EU’s largest country with more than 20m people than second-ranked France, Germany will tumble into third place. Poland, not far behind Spain today, will fall way back, with 20m fewer people than Spain in 2060.

It is hard to believe that such massive changes, which Eurostat says will take place in spite of immigration into the EU, would not have a big impact on the distribution of power in the EU. For example, the Lisbon treaty – which, of course, may never come into force – recognises Germany’s present pre-eminence by allocating Germany more European Parliament members than any other country. But that arrangement surely could not last if Eurostat’s forecast were to prove accurate.

As for Poland, its leaders cited its population size last year as an argument for more weight in the EU’s institutions. But if its population were to shrink as much as Eurostat predicts, it would be difficult to make the case that Poland deserves the same influence as, say, Spain.

Meanwhile, the UK would find itself in the remarkable position of being the largest country in an organisation that it has never seemed entirely sure it wants to be part of. Of course, the secession of Scotland (with just over 5m people now) from the UK would make a difference.

One glaring omission from the Eurostat report is Turkey, an official candidate for EU membership. Hostility to Turkey’s bid in countries such as Austria and France stems partly from the objection that Turkey is already so big (more than 70m people) that its admission would fundamentally change the EU’s nature. But I see that, according to a recent United Nations Population Fund forecast, Turkey will keep on growing and have over 100m people by 2050.

Given what Eurostat is saying about population trends in existing EU member-states, it would seem that opposition to Turkey’s admission will just get stronger and stronger.