We estimate the Intracluster Light (ICL) component within a sample of 18
clusters detected in XMM Cluster Survey (XCS) data using deep ($\sim$
26.8 mag) Hyper Suprime Cam Subaru Strategic Program DR1 (HSC-SSP DR1)
$i$-band data. We apply a rest-frame ${\mu}_{B} = 25 \
\mathrm{mag/arcsec^{2}}$ isophotal threshold to our clusters, below
which we define light as the ICL within an aperture of $R_{X,500}$
(X-ray estimate of $R_{500}$) centered on the Brightest Cluster Galaxy
(BCG). After applying careful masking and corrections for flux losses
from background subtraction, we recover $\sim$20% of the ICL flux,
approximately four times our estimate of the typical background at the
same isophotal level ($\sim$ 5%). We find that the ICL makes up about
$\sim$ 24% of the total cluster stellar mass on average ($\sim$ 41%
including the flux contained in the BCG within 50 kpc); this value is
well-matched with other observational studies and
semi-analytic/numerical simulations, but is significantly smaller than
results from recent hydrodynamical simulations (even when measured in an
observationally consistent way). We find no evidence for any links
between the amount of ICL flux with cluster mass, but find a growth rate
of $2-4$ for the ICL between $0.1 <z <0.5$. We conclude that the
ICL is the dominant evolutionary component of stellar mass in clusters
from $z \sim 1$. Our work highlights the need for a consistent approach
when measuring ICL alongside the need for deeper imaging, in order to
unambiguously measure the ICL across as broad a redshift range as
possible (e.g. 10-year stacked imaging from the Vera C. Rubin
Observatory).