Almost all research projects into stainless steels were interrupted by the 1914–18 War. The work was taken up again in the 1920s. Brearley had left the Brown Firth Laboratories in 1915, but the research continued under the direction of his successor, Dr. W. H. Hatfield. It is Hatfield who is credited with the development, in 1924, of a stainless steel which even today is probably the widest-used alloy of this type, the so-called "18/8", which in addition to chromium, includes nickel (Ni) in its composition (18wt% Cr, 8wt% Ni).