Those of us old enough to remember the debate over the Maastricht Treaty in the early 1990s remember the power of the ‘F’ word. Federalism.
Opponents of Maastricht insisted the treaty was a decisive step towards a federal European superstate.
Supporters employed their smoothest, most reassuring tones say that "no-one on the continent is talking about a federal Europe."
Well at least one person is now and he’s Manuel Barroso, no lesser figure than the President of the European Commission.
In his State of the European Union address to the European Parliament last week he told us not to be afraid of the word ‘federation’ and not as some distant dream; he is already working towards a new European treaty, involving the transfer of massive new powers to the EU, which he wants in place as soon as 2014.
There’s some acceptance in London that, if the Eurozone is to get itself out of its current hole, there is going to have to be some significant economic integration between the 17 members.
The Fiscal Compact Treaty, plans for a Banking Union, giving new powers to the European Central Bank, the European Court and to Brussels to oversee taxes and spending.
These are all things that many in London have accepted as inevitable if the Eurozone is to survive, and are prepared to go along with so long as the UK is not involved and they don’t impinge on our position within the single market.
But it is increasingly clear that plans for the next "great leap forward" go much further than doing what’s necessary to save the Euro.
Following hard on the heels of the Barroso speech came a wide-ranging list of proposals from a group of 11 EU states - led by the German Foreign Minister Guido Westerwelle - that would go way beyond anything that any UK Government (not just this one) could sign up to.
The list is spectacular in both its breadth and ambition.
There would be a directly elected European President and new powers for the European Parliament.
There would be a pan-European foreign ministry with greatly expanded powers to run an EU foreign policy decided by majority voting (so no vetoes by the UK or anyone else).
Defence policy would also be Europeanised, with the explicit aim that “this could eventually involve a European army”.
There would be a new EU police organisation to guard all external borders, with all visas run from Brussels.
Perhaps most controversially of all, in the future it’s proposed that EU Treaties could be changed by majority voting.
In other words, changes as significant as those in the Maastricht or Lisbon Treaties could simply be imposed on a country, whether it liked them or not.
And in case anyone still really believes that the UK is ‘winning the debate in Europe’ the list of governments backing these proposals include every major EU state except…Britain.
Germany, France, Italy, Spain and Poland are all behing them, although it has to be said that the debate in France over such a decisive move towards federalism is likely to be pretty lively.
How much of a problem is all this likely to be for David Cameron? Slightly counter-intuitively, such radical proposals may present him with less of a problem than small, incremental changes.
This is a programme for integration that stands absolutely zero chance of being endorsed by the UK electorate, so much so that it’s unlikely even the Liberal Democrats could endorse it.
With or without the ‘referendum lock’, it would have been politically impossible for any government in Westminster to enact such changes without consulting the electorate.
If Cameron were to be confronted with demands for small treaty amendments, a power transferred here, a competence enlarged there, he would be harried constantly by his Eurosceptic backbenchers over whether it is sufficient to trigger a referendum, and whether such a vote should be about one particular issue or turned into a final decision on whether to get in or stay out.
If the ‘Westerwelle Group’ are serious, there will be no such ambiguity.
Cameron will say no, his coalition partners will be unlikely to complain and while Labour will exploit Britain’s isolation and diplomatic failure, they won’t argue with the substance.
As to where this would leave Britain’s membership of the EU? Well that would become a very real question, and one that - after three decades or more of ambivalence - we may no longer be able to avoid answering.