  Using a sample of $>200$ clusters, each with typically $100-200$
spectroscopically confirmed cluster members, we search for a signal of
alignment between the Position Angle (PA) of the Brightest Cluster Galaxy (BCG)
and the distribution of cluster members on the sky about the cluster centre out
to projected distances of 3~R$_{200}$. The deep spectroscopy, combined with
corrections for spectroscopic incompleteness, makes our sample ideal to
determine alignment signal strengths. We also use an SDSS based skeleton of the
filamentary Large Scale Structure (LSS), and measure BCG alignment with the
location of the LSS skeleton segments on the sky out to projected distances of
10~R$_{200}$. The alignment signal is measured using three separate statistical
measures; Rao's spacing test (U), Kuiper's V parameter (V), and the Binomial
probability test (P). The significance of the BCG alignment signal with both
cluster members and LSS segments is extremely high (1 in a million chance or
less to be drawn randomly from a uniform distribution). We investigate a wide
set of parameters that may influence the strength of the alignment signal.
Clusters with more elliptical-shaped BCGs show stronger alignment with both
their cluster members and LSS segments. Also, selecting clusters with closely
connected filaments, or using a luminosity-weighted LSS skeleton, increases the
alignment signal significantly. Alignment strength decreases with increasing
projected distance. Combined, these results provide strong evidence for the
growth of clusters and their BCGs by preferential feeding along the direction
of the filaments in which they are embedded.
