If tasked against something as quick as a Bear it is difficult exercise to get an armed Hawk into the right bit of sky, let alone into missile parameters. Tasked against a simulated inbound Su-27 threat we didn't stand a chance. GCI update rate was just about good enough to defeat the first shots some of the time but beyond that we were toast, usually without ever seeing our adversary.
So what we need to do is ditch all these manned fighters and go over to an all missile defence system. Ahhh, good old Duncan Sandy was right
To be honest if Russia did invade, one feels the pitiful air defence we could put up would last days at the most.
It's not just the attrition that is the only worry, it is the fact that unlike WW2 you do not have the facilities to replace those lost in any meaningful time frame.