hectorm wrote: My elastic support strap goes straight from armpit to bottom of the pocket without the benefit of a button. I have to slide the laptop sideways stretching the strap and then, down in. Overall my underarm game pocket is bigger but it's not self finished with a handsome besom opening like Mr. Hillier's.
Regarding thornproof capability: the only thornproof I own is a Porter & Harding at almost 20 oz. and it's a beast. But this one is not the jacket with the game pocket. The "game" carrier it’s a Holland & Sherry corduroy at around 17/18 oz.I believe. My laptop is almost 3 pounds heavy and the jacket does not flinch.
Just as an aside, these large pockets are also known as 'poachers pockets', the idea being that you could get a salmon in it. The supporting strap can also be hidden under the lining but the visible strap is a nice version. Such pockets used for holding papers are also known as 'briefing pockets' being used by barristers in the past to hold their briefs.