Unknown Webb Carrier.

[dragnet]

Cant find this example, my first impression was some sort of respirator bag but with such a large amount of variety of custom bags used by British forces it has me scratching my head.

[welrod_man]

Not something I'd recognise as British Military.

[hayleyp]

Ww1

Looks like a ww1 offficers satchel

[John Bonnell]

Not British WW1. It looks to me like a variant of the WW2 Home Guard or ARP haversack.

[dragnet]

It’s respirator size,home guard/ARP use would fit the bill. Thanks for your help folks👍