This is the first recognisably modern computer, the Small-Scale Experimental Machine the SSEM, or Baby, the first to be able to store data plus operate an electronic memory. Built in Manchester, began running June 1948.
This is where the coding happened. The orange buttons input the zeroes and ones, the silver toggles below controlled the vertical positions of the code.
Baby was only built to prove it was possible to store information in such a way. But the first full scale machine based on its discovery was the Manchester Mark 1, built in April 1949.