I think this was covered in these forums a couple of days ago. It looked pretty obvious that some high-sided vehicle had impacted the Concorde nose cone and ripped it off.
What is more worrying is the general state of deterioration with the rest of the airframe. I have seen photographs where parts of the tail are now 'see-through' because of lack of attention.
If, as has been suggested, the aircraft still belongs to British Airways then perhaps the redoubtable Mr Willie Walsh should get off his @rse and do something about it.