  We discuss the $p p \to p p \gamma$ reaction at the LHC. We consider
diffractive classical bremsstrahlung mechanisms including effects of non
point-like nature of protons. In addition, we take into account (vector
meson)-pomeron, photon-pion as well as photon-pomeron exchange processes for
the first time in the literature. The integrated diffractive bremsstrahlung
cross section ($E_{\gamma}>100$ GeV) is only of the order of $\mu$b. We try to
identify regions of the phase space where one of the mechanisms dominates. The
classical bremsstrahlung dominates at large forward/backward photon
pseudorapidities, close to the pseudorapidities of scattered protons. In
contrast, the photon-pomeron (pomeron-photon) mechanism dominates at
midrapidities but the related cross section is rather small. In comparison the
virtual-omega--rescattering mechanism contributes at smaller angles of photons
(larger photon rapidities).
