  The sensitivity of the $^{12}$C$(\vec{\gamma},pd)$ reaction to photon linear
polarisation has been determined at MAMI, giving the first measurement of the
reaction for a nucleus heavier than $^{3}$He. Photon asymmetries and cross
sections were measured for $E_{\gamma}$=170 to 350 MeV. For $E_{\gamma}$ below
the $\Delta$ resonance, reactions leaving the residual $^{9}$Be near its ground
state show a positive asymmetry of up to 0.3, similar to that observed for
$^{3}$He suggesting a similar reaction mechanism for the two nuclei.
