Women workers of the Plessey firm work in London Underground railway tunnels during the war.  At the outbreak of war, the London Underground was in the process of extension and modification.  This involved the construction of new tunnels and the abandonment of some old stretches.  The resultant "unused" stretches of tunnel were intensively exploited for the war effort - as shelters, as secure storage and - as here - as underground factories.  

During the war, the Plessey company supplied the government with a range of goods, from electronics to shell cases.  These ladies are probably working in a five-mile section of (new) Underground tunnel on the Central line which had not been brought into service by the outbreak of war.  Other abandoned/uncommissioned tunnels in London, as well as tunnels and caves of all sorts across the UK, were employed in "unconventional use" in the interests of the war effort.  Best regards, JR.

Deeper and down ... "Underground" workers ...

The "Dig for Victory" phenomenon - officially-promoted campaigns encouraging civilians to grow food in their gardens, allotments, "victory gardens" or whatever - was common in combatant nations during WW2.  This, of course, was largely an urban phenomenon, as all usable land outside urban areas (even a great deal of land hitherto regarded as unworkable) was applied to general (if intensified and centrally directed) agriculture and animal husbandry).  

The intensity and originality of the British "Dig for Victory" campaign - a result of a combination of severe constraint on food supply and the need to persuade individuals to comply "democratically" - has drawn particular historical attention to it.  This has - at least in the English-speaking world - tended to draw attention away from other cases where the former condition (of food shortage) applied, but where the need for "democratic" persuasion applied to a lesser extent.  An example is the cities of German-occupied France.  This remarkable photo shows French civilians tending vegetables ... in a courtyard of the Palais du Louvre, by the banks of the Seine in central Paris.  Since the Palace was in German/official hands, this was, presumably, part of an officially-sponsored (or ordered) allotment or "victory garden" system.

I would be interested to know more about the "victory garden" phenomenon in urban Germany and occupied Europe - I have little doubt that there was one.  Was there a French equivalent of Britain's heroic "Dr Carrot"?  Was there a Pomme-de-Terre Pierre ?  At this stage, I could not say ... Best regards, JR.