Mode S is a standard part of every ACAS II installation as that is required to provide the datalink channel for coordinated manouvers. And that sends out a RA alert mesage which could be displayed on the controllers screen, but sadly is not in most installations.
I do not know how all over europe the mode-s ground infrastructure is at the moment, however it seems that the local ATC provider are working on implementing mode s into their infrastructure. In germany all radar sites have been upgraded to be mode s compliant, however most of the mode s data is not used and displayed to the controller. At the moment only the Flight ID tag is displayed as far as i know. The official reason is that as long as the flight ID still shows a failure rate of more than 1% (most of it crew-induced) it has to be assumed that the other data is invalid as well and therefore cannot be used.