Is about 14 days?

Politaholic has just watched Thursday's Question Time on BBCIPlayer and it looked to me as if David Davis was skewered over the 42 days, chiefly because he voted in favour of 28 days. On his blog Davis argues that he supports 28 days as a "necessary evil" but "not a day more". So its about 14 days not 42? Of course, we all know that we have to balance security against liberty, but if you support 28 days and oppose 42 you can hardly argue, as Davis has been, that this is a matter of principle. I suppose the principle could be "no longer than is strictly necessary"; but then how long is necessary is - it seems - a pragmatic calculation. After all, I suppose those who support 42 days or 90 days also do so on the grounds that it is a "necessary evil". Frankly, I doubt that 42 days is necessary (and from what I have read in the papers that, it seems, is the view of M15 as well). Remember we are not talking about the police having enough evidence for a conviction; merely enough evidence to bring a charge. If they can't do that after 42 days one wonders why they have the poor devil in custody in the first place. Indeed, 28 days seems too long to me.
More generally, although Davis opposes the spread of CCTV and ID cards, he also opposes the Human Rights Act and supports capital punishment, not conventional liberal standpoints.
The argument about CCTV is also complicated. I personally don't like them; but there is no question that in working-class inner-city areas they are popular, and one can understand why.
I'm afraid that so far as Davis is concerned I can't quite swallow the "man of principle" pitch; perhaps I am just too cynical, but I think this is about self-promotion and the Conservative leadership. We are all assuming that Davis has given up the prospect of becoming Home Secretary if the Tories win the next election. Davis may have sensed that Cameron had other plans.
I seem to remember, many moons ago, reading something about Davis in the Guardian Diary concerning his time in the Territorial SAS. It seems, in a training exercise, he planned an ambush, arranging his men on opposite sides of the road and instructing them to open fire as the target passed. Until someone pointed out that, facing each other on opposite sides of the road, his men were in each others line of fire...