  Considering the BFKL and DGLAP QCD evolution equations for structure
functions, we discuss the possibility of unifying them in the whole $x$ and
$Q^2$ range. We emphasize that the main problem is related to the constraint of
angular ordering of the radiation, and the cancellation of the related
collinear singularities for inclusive processes. At the leading log\ $1/x$ and
log\ $Q^2$ level, we write down a unified system of equations satisfying this
cancellation constraint. At low $x$, it leads to a less singular behaviour of
the structure functions than the BFKL prediction.
