The 1944 Pattern officer’s haversack was closely based on that designed for the 1937 pattern set but lacked the interior pockets of the earlier design. It was designed to act as a small briefcase for pens, papers, and other small administrative items an officer needed to perform his duties in the field. The haversack was rectangular in shape, measuring 19 inches by 9 inches and was 2 inches wide:
The haversack had a large top flap secured by a single central buckle:
A pair or buckles on the rear allowed it to be hung from the brace ends:

A small webbing grab handle was sewn between these so the haversack could be carried like a briefcase if preferred.
The interior of the haversack was lined with waterproof fabric to help protect the contents and this extended halfway up the interior of the top flap:
two weather flaps on either side were also provided to further protect the papers within- unusually these were cut to a point rather than being square:
Although faint, the markings on the underside of the top flap date this example to 1945, although it would continue in production into the 1960s at least. The initials MW&S indicated that Michael Wright and Sons:

The officer’s haversack is probably the hardest component of the 1944 Pattern set to track down, despite its lengthy production life it does not seem to have been very popular and examples are scarce today.
Another “I look different, shoot me first” piece of kit.
It looks like a useful thing to have and issuing one to everyone might have been a good idea. That would only leave map cases, binoculars, sidearms etc. to point subalterns out for immediate attention;)