The word for the day is Kakistocracy.
I totally get the UK is weak on crime. Any country that can be duped into believing that restricting access to hand-held weapons will make a population safe has serious issues with logical thinking. I don't know if it's the lack of decently prepared red meat, a diet consisting mainly of fish and chips, jellied eels, and spotted dick, or living in a country where the sun is only seen 1 day a year, for an hour, at sunrise. The UK has weird laws and even weirder judges to interpret those laws. They are, quite simply, weak on terrorism.
On our side of the pond, I'd like to think we'd do better. Failure to secure the United States, or seek Justice for those murdered, after trying to seek justice and failing is ineptitude; but for failing to act at all, is willful neglect of responsibilities. Given the hand full of aces we currently hold with the UK, in terms of their need to ameliorate the relationship with the US after Deepwater Horizon, one would think a little diplomacy could have resulted in transfer of the terrorist to a US prison, where he would receive adequate healthcare, greater than he could imagine in his home country. Instead, while the US holds four aces, it seems the State Department is assuming the UK, or Libya, has drawn a royal flush, on a four-card draw. (The odds of that happening are approximately 649,739 : 1.)
It does make one wonder if it is ineptitude, or malicious intent.