We present the results of a deep optical-near-infrared multi-epoch survey covering 2.5 square degrees of the Pleiades open star cluster to search for new very-low-mass brown dwarf members .
A significant ( \sim 5 year ) epoch difference exists between the optical ( CFH12k I - , Z -band ) and near infrared ( UKIRT WFCAM J -band ) observations .
We construct I , I - Z and Z , Z - J colour magnitude diagrams to select candidate cluster members .
Proper motions are computed for all candidate members and compared to the background field objects to further refine the sample .
We recover all known cluster members within the area of our survey .
In addition , we have discovered 9 new candidate brown dwarf cluster members .
The 7 faintest candidates have red Z - J colours and show blue near-infrared colours .
These are consistent with being L and T-type Pleiads .
Theoretical models predict their masses to be around 11M _ { Jup } .