Small x resummation in collinear factorisation

summation of the small x-corrections to hard-scattering QCD amplitudes by collinear factorisation method is reconsidered and the K-factor is derived in leading ln x approximation with a result differing from the corresponding expression by Catani and Hautmann (Nucl. Phys. B 427, 475, 1994). The significance of the difference is demonstrated in the examples of structure function FL and of exclusive vector meson electroproduction. The formulation covers the channels of non-vanishing conformal spin n paving the way for new applications.