The excellent answers to What are these circular spots on these Ariane V SRB nozzles? tend to indicate that unlike the IV, the Ariane V simply rests on two flat surfaces under the SRBs at launch time, and does not have a lock down mechanism to hold it in place until proper ignition and full thrust can be confirmed.
Those answers contain a lot of information and are worth reading.
Assuming this is the case, what would happen if for some reason one of the SRBs did not ignite at all, or started burning with substantially lower power, say less than 50%, or the nozzle failed promptly? (like this one did at the end of a test)
Question: Would the rocket fail to leave the ground and just sit there and burn, or would the resulting torque tip it over? Or would the auto destruct mechanism blow it up on the pad?