  We test through stellar N-body simulations some scenarios to explain the
dynamics of the peculiar nucleus of the Andromeda galaxy (M~31): although HST
observations reveal a double nucleus morphology, the rotation field is almost
symmetric around the bulge gravity centre and the velocity dispersion is
off-centred. We show that any m=1 perturbation has a very short life-time (a
few 10$^5$ yr). Assuming that the bright peak (P1) is a cold stellar cluster
infalling into the nucleus, and that the large central velocity gradient is due
to a central dark mass (in the range 7~$10^7$--$10^8$~\Msun), we obtain a
reasonably good fit to the observations. However, if this cluster lies in the
central 20 pc, we estimate the life-time of the cluster to be less than
0.5~Myr. The dynamical friction is more efficient than estimated by analytic
formulae, and is essentially due to the deformation of the stellar cluster
through the huge tidal forces provided by the black hole. We show that the
cluster cannot be on a circular orbit around the centre if the nucleus hosts a
massive black hole of a few $10^7$~\Msun, and finally provide some estimates of
the kinematics as observed with HST.
