I would hazard a guess that inbound aircraft would not be greatly affected by virtue of management providing a limited cover and short haul diverting or more than likely being cancelled. At LHR (I stand to be corrected) there seems to be little talk about it and not a great deal of appetite. One of the largest groups within the BAA plc and its limited companies are the Security and I am confident that senior management are up for a fight if the outcome might be outsourcing this particular group. Other than limited scope for diverts to MAN, LTN and BHX there are very few airports availible to provide resources for longhaul aircraft.