There has been much talk of a big cut in that assistance - it is being seriously discussed now. Plus the setback in UI and cross-border job opportunities by a hard border. Combined, this will flame hardline republican sentiment (left of Sinn Fein), as well as loyalist discontent with setbacks. This would cause increased military presence from England, which would add more fuel to the flames, and things could easily spiral back into violence once again. Historically, these things tend to flame up every few decades in Ireland.