The high intensity frontier

In these last years, there is an unprecedented world-wide consensus on the next steps to be taken in the construction of major "energy frontier" accelerator facilities. The main threads for the future of world particle physics seem clear: the first priority is the completion and commissioning of the large hadron collider (LHC), the next priority is the construction of the TeV-energy LC, with a significant period of overlap with LHC running. If the "energy frontier" for the future activities in particle,physics seems to be well defined, it is becoming more and more relevant and urgent to underline the importance of other facilities for particle physics. This Report focuses the importance of a diversified experimental program in flavour physics during the LHC era. In particular this Report presents the great opportunities, offered by flavour physics, on a number of fronts within the quark flavour sector, K and charm physics, as well as within neutral and charged-lepton sector, neutrino physics and physics of lepton flavour violation. Finally it is briefly illustrated how future high intensity facilities may also offer an opportunity to perform frontier experiment in nuclear physics