This is part of a ICAO initiative, and the TSA has been the most keen participant (they presumably see the cost reductions that comes from this). So the TSA is pushing this most, and so they are first in the LHR context. But rest assured, the EU is also in the loop and has actioned it at their airports, and will presumably participate at LHR in due course. It's about bilateral discussion and the USA tends to be slicker at this than other players. The other players are Canada, UK and Danish Crown Dependencies, and Montenegro.