With weary familiarity, we can see the same old pattern emerging. First, appointing a pan-European "super prosecutor" was one of Blair's "red lines". Then, under pressure during the constitutional convention, British negotiators conceded that the post could come into existence, but only if all 25 EU member states agreed - a so-called "unanimity lock".
Now, according to a report in the Telegraph, Franz-Hermann Brüner, director general of the European Anti-Fraud Office, is preparing us for the next stage.
Speaking at a seminar at the European Parliament in Brussels, Brüner - a German former judge - has cast doubt on the security of the "lock".
He said preparatory work on establishing the office of European public prosecutor - who would outrank national prosecutors on crimes involving EU funds - was already under way and argued that the EU constitution was "removing the walls" currently enforcing a strict separation between the union and national criminal justice systems.
British officials are still insisting that the "unanimity lock" is enough to block the creation of a pan-European prosecutor, but Brüner disagrees. "Hopefully we will have a constitution in 2007-2008," he says, "and that will be the legal basis [for such a prosecutor]. In the meantime, we will continue with the preparatory work."
Unnamed EU legal experts seemed also to support Brüner, suggesting that the "lock" could be overcome, with one noting that in Brussels, voting rules can change, and have done so in the past.
This is all so familiar – a process that has been described as "engrenage" or "salami slicing". Others might call it the "thin edge of the wedge" technique.
First, a proposal is dismissed as unacceptable. Then is accepted as a vague objective, to be achieved at some unspecified time in the future. Then it is given substance, with objectors assured that they can veto the final plans. Then the veto is whittled away, and finally the original proposal – which everyone assured us was never going to happen, is adopted.
How often have we been there, and how many more times are our leaders going to fall for it?