  We discuss the process of colour-singlet parton-parton scattering, which in
hadron-hadron collision can lead to production of jet events, where a rapidity
gap between the jets is present. The dynamics of the process is calculated
within LL BFKL approximation. Using Pythia MC generator, hadronic shapes of
jet-gap-jet events are studied, in particular the distributions of the rapidity
gap size resulting from the jet formation processes. Using Pythia's modelling
of multiple parton interactions, the rescattering effects are simulated. It is
shown how these effects influence the gap size distributions. The kinematic
dependence of the gap survival probability is discussed.
