  For the first time, a next-to-leading BFKL study of the cross section and
azimuthal decorrellation of Mueller Navelet jets is performed, i.e. including
next-to-leading corrections to the Green's function as well as next-to-leading
corrections to the Mueller Navelet vertices. The obtained results for standard
observables proposed for studies of Mueller Navelet jets show that both sources
of corrections are of equal and big importance for final magnitude and final
behavior of observables, in particular for the LHC kinematics investigated here
in detail. The astonishing conclusion of our analysis is that the observables
obtained within the complete next-lo-leading order BFKL framework of the
present paper are quite similar to the same observables obtained within
next-to-leading logarithm DGLAP type treatment. The only noticeable difference
is the ratio the azimuthal angular moments < cos 2 phi >/ < cos phi > which
still differs in both treatments.
