As you might have gathered I am not sold on either set of opinions, all I can say is that when asked the questions are being answered.
The devil is as ever in the detail and bandying about how you get 20 minutes and whether its 97% or 98% is difficult to rebutt as I have not actually asked the question in those terms simply because at this stage of the game those values are guesses [potentially and hopefully good or inspired ones].
If 20 minutes is from in flight rather than from bottoms on easy chair that sort of makes sense. The 902 and the 135 do not start up at exactly the same rate [do they?] so there must a line drawn in the sand somewhere..... perhaps rotors running.
In my office I have a police poster created by Essex, Suffolk and Cambridge when they flew AS355 and Suffolks faster 135. It was produced at an enlightened time when nobody thought to question its message [as in NPAS] so it wasn't controvercial [then].
On that poster nowhere in the three police areas was outside 15 minutes from their own slowish 355 aircraft and Suffolk's faster 135 could reach anywhere on that patch [of three counties] in 20 minutes from Wattisham.
One 'NPAS lie' that is being bandied about is this 24/7 thing. As of today the UK does not have 24/7 police helicopter availability - fact. As of Monday the South East has 24/7 police helicopter availability and when its all in place 2015 [ish] England and Wales will/should have 24/7 police helicopter availability.
Of course its a bit of a farce really.... near pointless for some ..... the Met provides the [nominal] 24/7 in SE but we all know that they are not going to despatch an EC145 at 4-30am to a PC standing in Dover Castle who has lost his car keys and wants a searchlight. Clearly not important enough and too far. But a less silly example in Chelmsford, Watford or Redhill might stand a real chance of getting air support at such a time and something really important in Portsmouth might get there too.
When the Marchioness went down in the River Thames the Met were tucked up in their beds. That disaster eventually changed how they perceived 24/7 and led to them being 24/7. That is not flying, it is available....... at the drop of a hat.
There are lots of if buts and maybees but nominally 24/7 is certainly a plus point for NPAS even if the time of arrival at 0500 is most certainly not going to fit into the 20 minute bracket.