JACK MERRIDEW

“A little boy who wore the remains of extraordinary black cap on his red hair and who carried the remains of a pair of spectacles at his waist, started forward, then changed his mind and stood still.”

My personal interpretation is that the “little boy” is just Jack Merridew from the Officers perspective as he has no authority and power to the Officer - he’s just a boy. This is backed up by the “red hair” which Jack has, and the “extraordinary black cap” which is the remains of the civilized person he was before. And the glasses part doesn’t really need to be explained... 

But the end bit its like “he changed his mind,” so like, he goes to say something and tries and make his point but then realizes he has no power against the Officer.