The 1937 pattern bayonet frog had been designed to carry the long sword bayonet of the SMLE in its leather scabbard. When the short No4 ‘pigsticker’ type bayonet was introduced along with its tubular metal scabbard it was discovered that the scabbard was prone to slipping out from the frog and bayonets could be lost. Although the webbing would be modified to work better with the new bayonet and its scabbard, a short term expedient was needed to allow the new bayonet to be carried in the existing frog. The ‘tab, securing, bayonet, No.4, Mk I’ was adopted on 26th July 1940:This simple device consisted of a leather tab, with a slot cut in it:This was threaded over the boss on the bayonet scabbard before it was slotted into the frog:The opposite end had a stamped brass eyelet:When the bayonet was inserted in the frog, the tab was folded over the top of the uppermost webbing loop and secured to the boss with the brass eyelet:This held tension on the scabbard and prevented it working loose. Although the bayonet frogs were soon modified, the tab remained in inventory until at least 1974 and lasted long enough to be allocated an NSN number.

Examples of the securing tab can be seen in period photographs:Whilst these tabs were used, many soldiers used the expedient method of cutting a small slot in the frog to better fit the boss of the scabbard, and in 1944 this was adopted as the official method of modifying the frog and the tabs became obsolescent, although clearly remained in inventory for at least another thirty years!