  Nuclear and starburst activity are known to often occur concomitantly.
Herschel-SPIRE provides sampling of the FIR SEDs of type 1 and type 2 AGN,
allowing for the separation between the hot dust (torus) and cold dust
(starburst) emission. We study large samples of spectroscopically confirmed
type 1 and type 2 AGN lying within the Herschel Multi-tiered Extragalactic
Survey (HerMES) fields observed during the science demonstration phase, aiming
to understand their FIR colour distributions and constrain their starburst
contributions. We find that one third of the spectroscopically confirmed AGN in
the HerMES fields have 5-sigma detections at 250um, in agreement with previous
(sub)mm AGN studies. Their combined Spitzer-MIPS and Herschel-SPIRE colours -
specifically S(250)/S(70) vs. S(70)/S(24) - quite clearly separate them from
the non-AGN, star-forming galaxy population, as their 24-um flux is dominated
by the hot torus emission. However, their SPIRE colours alone do not differ
from those of non-AGN galaxies. SED fitting shows that all those AGN need a
starburst component to fully account for their FIR emission. For objects at z >
2, we find a correlation between the infrared luminosity attributed to the
starburst component, L(SB), and the AGN accretion luminosity, L(acc), with
L(SB) propto L(acc)^0.35. Type 2 AGN detected at 250um show on average higher
L(SB) than type 1 objects but their number is still too low to establish
whether this trend indicates stronger star-formation activity.
