Even the setting speaks volumes about the message. New Cardiff, New Britain, New Labour, and soon, under British leadership, New Europe. Or so they will have us believe.
This city has been born again. Archetypical of the decline of old manufacturing in Britain, once its greatest coal port, it is now a symbol of both economic transformation and the great British political reform project, as the seat of the new Welsh consultative assembly.
Where better then to show Europe's leaders Cool Britannia? Where better to continue the process of rebranding the EU?
Leaders will take advantage of the thinness of their formal summit agenda to open up major discussion at lunch today on where the EU is going. In part this is a response to the Kohl/Chirac presummit letter, a chance for the German Chancellor to do some electioneering Brussels-bashing at perhaps his last summit.
The theme of subsidiarity suits the British Prime Minister, Mr Blair, well, playing nicely with his insistence that Europe is learning to moderate its ambitions. Some attempt may well even be made to operationalise the general principles of subsidiarity by drawing up a broad list of policy areas where the EU will and will not operate.
In part the debate will also be about how to address the institutional questions the Amsterdam Treaty left unanswered - the weighting of votes in the Council of Ministers, the number of Commissioners, and the possibility of extending qualified majority voting.
All are seen as crucial ahead of enlargement and the British have in the last week been floating the idea of a rapid mini-Intergovernmental Conference next year to deal with them - if that requires a constitutional amendment and hence a referendum in Ireland, the prospect will scarcely fill the Taoiseach with glee.
On Friday, the President of the Commission, Mr Jacques Santer, added to the list a suggestion for the reform of the General Affairs Council. The council is currently run by foreign ministers and its agendas have tended to be dominated by external issues rather than the co-ordination of internal policies.
Mr Santer suggested that the problem could be remedied if the member-states considered appointing a senior other minister to the GAC, to be based almost full time in Brussels.
In his pre-summit letter to leaders, Mr Blair suggests that they should take a look over lunch at whether they need to address the question of the EU's democratic legitimacy.
The scarcely resounding ratifications of the Amsterdam Treaty in Ireland and Copenhagen demonstrated how little the treaty's "citizen-friendly" preoccupations have actually bridged the chasm between elites and the public over European integration. Other approaches may well be needed and the recent initiative of the former President of the Commission, Mr Jacques Delors, may well get a first airing.
Mr Delors suggested that some legitimacy could be given to the next president if he or she were to be nominated by the parties in the European Parliament and be approved informally by the electorate when they vote for MEPs next June. The heads of government would then have a choice of two or three candidates with a form of democratic mandate.
It is a broad agenda for one lunchtime discussion and perhaps too indigestible to produce more than a pledge to go on working on the issues, perhaps through a high-level working group of prime ministers' personal representatives.
Another opportunity for controversy will come after lunch in the discussion on Agenda 2000, the Commission's programme for the post-2000 budget, when the Germans have signalled their intention to raise again the issue of their "unfair" net contribution to the EU budget. Mr Santer is due to produce a report on the issue - after the German elections - and most member-states, Ireland included, will argue that any discussion is premature.
Others, such as the Spanish, may be tempted to engage in a more substantial discussion on the principle of what is being called the juste retour, or fair return on contributions, which Mr Santer denounced on Friday as an attack on the solidarity of the EU - any substantial rebate to Germany, a la Thatcher, would have to be paid for by the EU's least wealthy members.
This morning the leaders will debate the EU's broad economic guidelines, strictures on the member-states to continue the valiant work of budget consolidation that has made the euro possible. They are unlikely to restore the country-specific recommendations made by the Commission but carefully filleted from the document by finance ministers who, like Mr McCreevy, did not relish having their room for manoeuvre seriously constrained.
Employment strategies of member-states will also be discussed - in line with the conclusions of the Luxembourg summit, each capital has submitted its plans for reform of its labour markets for a form of peer review.
The Commission's initial report on the plans was favourable, pointing particularly to two star pupils, France and Spain.
Most of the foreign policy issues will be left to foreign ministers, meeting separately. Declarations are expected to confirm the NATO strategy of increasing pressure on Serbia over Kosovo with the threat of potential military action as a last resort, to express concern at the stalemate in the Middle East peace process, and to confirm sanctions against India and Pakistan over their nuclear tests.
President Nelson Mandela of South Africa will come to lunch tomorrow for what was hoped to be the signing of a major trade agreement between the EU and South Africa. The deal is not yet done, however, so leaders will use the occasion simply to pay tribute to Mr Mandela before he retires from the political stage - and, no doubt, to bask in his reflected glory.
Perhaps the trickiest foreign policy problem, however, will be the British determination to extend some kind of olive branch to Turkey, whose acrimonious relationship with the EU is a cause of major embarrassment.
But the main message of the summit will be that Britain is now a team player, no longer a hurler on the ditch, with a game plan, whether drawn up in London or elsewhere, that stresses a broadly common purpose. Times have changed.