Until 1942 Wilkinson Sword had been the only company which produced the F-S knives. In 1942 there came two more manufacturers.
One was later known for its acceptance mark “ B2”. It was made according to the drawings of the black hilt 2nd Pattern Wilkinson F-S knife. The close resamblance is the reason why many collectors assumed that the acceptance mark B2 stands for Wilkinson.
Finally proof was found by Robert Wilkinson-Latham that Wilkinson Sword actually produced the knives marked “ B2”. Wilkinson Sword and J. Clark & Son were the only known producers of these early 2nd Pattern F-S knives.