I discuss the possibilities for using the LHC as a photon colliding
machine. The photon parton density is quite precisely known and I
consider the implications for the LHC phenomenology. In addition,
the colour singlet nature of the photon means that it can readily
lead to exclusive or semi-exclusive events, with limited or no extra
particle production in the final state. I will show how such  processes,
in particular in combination with proton tagging measurements, provide
a well understood environment in which to test the Standard Model and
search for the BSM physics. I shall focus on a few topical examples.