If the Government as whole, MOD Dept of transport and branches of the military along with the owners of LHR and LGW all behaved in a tardy and inefficient manner then it surely will result in a mass cover up as they all back each other up. It is however very much an example of UL 2018/9 that people do not do the bleedin' obvious usually because some accountant has ruled theres no business case for it or it doesnt 'drive incremental revenues' (and therefore my bonus as CEO where spending a few million is a cost and that negatively affects my businesses as CEO. In fact it probably a certainty that neither CEO has 'keep airport operating in all reasonable circumstances as an objective anyway' . Protection from drones is certainly within today's world of reasonable circumstances.
I do not blame the military that much though, they do what they are asked and if no one asked them to prepare for this threat it is not their fault but it does show a stunning degree of unpreparedness for something thats been discussed on here -just one example-for years.