Haymarket hector, n. — Green’s Dictionary of Slang

Haymarket hector n.

[proper name Haymarket, a centre of London prostitution + hector n.; cit. 1675 may have a different meaning, i.e. a thug rather than pimp: the Haymarket, still a literal market in late 17C was only a centre of prostitution in 18C–19C]

a pimp.

c.1675		Marvell ‘Cutting of Sir John Coventry’s Nose’ in Aitken Poems and Satires II (1892) 202: O ye Haymarket Hectors, How were you thus charmed.
1873		Sl. Dict. 189: Haymarket Hectors bullies who, in the interest of prostitutes, affect the neighbourhood of Leicester Square and the Haymarket.
1882		Sydney Sl. Dict. (2 edn) 5: Haymarket Hectors - Bullies who, in the interests of prostitutes, infest the neighbourhood of Leicester Square and the Haymarket.