Scattering amplitudes in the (multi-)Regge regime develop large logarithms, which depend on the ratio of the centre-of-mass energy over the transferred momentum, to all orders in perturbation theory. The resummation of these logarithms relies on the universal building blocks of high-energy factorisation, which can be associated with the properties of either a Regge pole or a Regge cut in the complex angular momentum plane. Both the cut and the pole contribute to the tower of the Next-to-Next-to-Leading Logarithms (NNLLs) and it becomes non-trivial to distinguish them at the level of the perturbative expansion of the amplitudes.
This contribution describes a framework to determine the building blocks of high-energy factorisation and then focus on the (multi-)Regge limit of the amplitudes with external quarks and gluons, as well as the Higgs boson.