  Uncorrelated variability between direct X-ray continuum and reflection
components (including the Fe line, if present) has been reported in many
accreting black hole systems, challenging theoretical models of disc
reflection. We explore a model based on gravitational light bending in the near
vicinity of the central black hole in which the X-ray variability is controlled
by the height of the primary source of X-rays above the accretion disc. The
relationship between the direct power law component (PLC) and the
reflection-dominated component (RDC) is not trivial and allows to identify
three different regimes in which the RDC (and the Fe line) is correlated,
anti-correlated or almost independent with respect to the PLC. X-ray
observations of the active galaxy MCG-6-30-15 and the black hole candidate XTE
J1650-500 (and possibly other sources, e.g. NGC 4051) reveal that a series of
predictions are actually observed: the behaviour of the Fe line flux, profile,
and EW and of the reflection fraction with respect to the continuum supports
our model which may explain what are otherwise puzzling properties of these
sources.
