The Daily Express (page 4) places the headline 'Remember Hongkong!' above a story about a sinking in the Singapore region.
This seems to be the first use of a slogan - repeated in an editorial of April 8, 1942 - that will be turned into a poster and displayed on the walls of some workplaces: http://gwulo.com/node/13783.
It seems that Eden's speech (http://gwulo.com/node/11079) has burnt the atrocities that took place during and shortly after the fighting into the public consciousness. They're one of the first things that come to the mind of family and friends when they think of their loved ones held in Hong Kong.