For many years after the new art deco fronted building was opened in 1939 the work was carried out in laboratories fronting on Euston Street, London, NW1.  These included three parallel four-story blocks of laboratories and offices with the basements being used for the heaviest equipment and for storage of samples. The Euston Street building was extended to the right of the main entrance making the address 81–103 Euston Street, with the laboratories behind being in Regnart Buildings and Euston Buildings which fronted on Stephenson Way. The extension was opened on 13 May 1959 by Sir Alexander Fleck.  In the mid-1950s Prince Philip, Duke of Edinburgh toured all departments. 
The laboratories were grouped in specialist sections, including analytical chemistry, corrosion, creep testing, electroplating, fatigue testing, general metallurgy, information library, mechanical testing, melting and casting, members liaison, metallography, metal working, physics (X-ray crystallography), and spectrography. 
The laboratories were an excellent training ground both for assistants who studied for their qualifications part-time and for recent graduates from universities.  As such members found that staff could be ideal recruits for industrial work.  There were 150–200 staff and the average time for researchers to stay was about three years and they could then be found in industries in Britain and worldwide. From the late 1930s to the 1960s through the war and then post-war recovery the Director was Mr G. L. Bailey with Miss E. M. (Helen) Hills as his secretary.