The announcement next week by the British that they intend to sign up to substantial parts of EU police and judicial co-operation in the Schengen agreement, disclosed by The Irish Times on Wednesday, will mark another significant landmark in the gradual softening of London's attitude to things European.
Britain's partners will take particular note that the decision comes only a couple of weeks after the Prime Minister, Mr Tony Blair, gave the go-ahead to preparations for a changeover to the euro.
The move, which will free Ireland to sign up to Schengen as well, is due to be matched by a parallel announcement that the UK also intends to take part in the EU harmonisation of its treatment and procedures for handling asylum-seekers. On Wednesday the Commission announced an initiative on asylum and this is due to be discussed next Friday at a meeting of Justice and Home Affairs ministers when the British are expected to make declarations on both issues. Irish official sources say the Government is expected to follow suit.
The Amsterdam Treaty provides a five-year time frame for collective decisions on asylum, immigration and visa issues, with opt-outs for Britain and Ireland. But Ireland made clear that its opt-out was primarily related to the desire to preserve the common travel area with the UK, which required common rules concerning those who come from abroad.
Although both announcements may yet prove controversial, they are not altogether surprising. The change in government in London before the Amsterdam summit allowed for significant breakthroughs in the treaty's contents and structure.
The Schengen Treaty, which is designed to promote passport-free travel between EU member-states and Norway, was incorporated into the treaty with opt-outs for Britain, Ireland and Denmark. Perhaps even more significantly from a constitutional point of view, leaders were able to move provisions on common asylum, immigration and visa rules from the intergovernmental, so-called Third Pillar of the Treaty, to the collective decision-making of the First Pillar. What this means is that instead of cumbersome international conventions being needed to deal with such questions, directives can be agreed by ministers.
The importance of this was that even though Britain had its opt-out (and a subsequent opt-in option to all or some of the provisions), it was in effect conceding that issues close to its concept of national sovereignty could be decided collectively at European level.
But Britain - and Ireland - will make clear that their decision to opt in to elements of both forms of co-operation will not stretch to the ultra-sensitive questions of immigration and visa controls, which actually represent the bulk - 75 per cent - of the data exchanges via the Schengen Information System (SIS) database, which has been attacked by civil liberties groups. Passport controls will remain and inputs to and use of the SIS will be confined to data on stolen cars and extradition warrants.
Diplomats also warn that Britain's willingness may not be sufficient to guarantee participation. A lapse in concentration in the final moments of the treaty negotiations by both Irish and British leaders let Spain insert a requirement for unanimous consent among Schengen members before others would be allowed to sign up. Spain may be willing to wield its veto against UK participation because of their dispute on Gibraltar.
Sources have also made clear that the Irish do not regard the Schengen agreement's encouragement to member-states to reach agreement on "hot pursuit" as a runner. Although willing to strengthen North-South security collaboration, officials believe that the possibility of British troops or the RUC pursuing suspects across the Border into Dundalk to be politically unacceptable.
They may well be right.