Vintage Canvas/webbing shoulder / Respirator Mask bag? Military Issue Bag 1954

I believe this is a British army issue respirator or equipment bag.

It is stamped inside with the makers name and the date 1954 and the war Dept Arrow.

It has 3 separate compartments inside.

The bag is in good condition obviously it has some marks and stains ,but no rips or tears to the bag .The strap is a darker colour than the bag.

I cannot really give a better description as I am not a collector of military equipment.