  The largest radiative corrections to the cross section of electron-proton
scattering at high energies are associated with emission of photons, real and
virtual, by electron. They contain large logarithms coming from soft and
collinear photons. Cancellation of the contributions of the soft photons to
virtual and real corrections is well known. Less known is the fact that the
contributions of the photons collinear to scattered electrons are also
cancelled for the most of experiments. On the contrary, contributions of the
photons collinear to initial electrons as a rule are not cancelled. It is
shown, however, that these contributions are cancelled for the experimental set
up suggested by A.A. Vorobev for measurement of proton radius.
