in my H.O. Darling is talking rubbish. This is all a bluff.
The UK armed Police is already massively overstretched, with the likes of SO19 and many county units working vast amounts of overtime just to keep those on the ground safe.
I am unaware of any basis in avaition law which dictates to an airline that thou shalt have an armed guard in one of thine paying seats. They are commercial companies working to the law and are unlikely to bend to a whim of the Government. Indeed, there are human rights issues here!
I like to think myself reasonably well connected in Police firearms circles and I haven't heard anything!!!!!!!!!!!!!!!!!!
(retire to drawing room with large port and await men in black suits)