July 1954. RN Recruiting Office London, I thought it was in the Charing Cross area but I can't find one there now... Well, 64 years on, what d'ya expect !

There were about a dozen of us, sat there waiting for some sort of test.

It turned out to be a practical test for colour perception. 

A CPO was explaining that we would each have to look through an eyepiece protruding from one of the walls, it looked like sawn-off eyepiece from a telescope.  All we had to do was sing out the colour of the light as it changed.

"The light will be RED, GREEN or WHITE...  First one up... You" !   Pointing to the nearest chap...

This chap stands up to the eyepiece, looks through it and calls out in a nice clear voice "BLUE" !