Green’s Dictionary of Slang

namesclop n.

a policeman.

1859, 1860		Hotten Dict. of Modern Sl. etc.
1861		(con. 1840s–50s) H. Mayhew London Labour and London Poor I 23/2: Cool the namesclop ... Look at the police-man.
1870		Hotten Sl. Dict.
1873		Sl. Dict.
1882		Sydney Sl. Dict. (2 edn) 11: Nam Esclop - A policeman.
1890		Northampton Mercury 12 Apr. 12/4: ‘Back-slang’ , pure and unadulterated for ‘policeman,’ is ‘namesclop,’ this being shortened down to ‘sclop,’ gives us the common word ‘slop’.
1892		Lloyd's Wkly Newspaper 3 Jan. 6/5: You hav'n't been copped by a namesclop, have you, Joe?