Why have statutory minimum wages become more prominent in recent decades? Why have they generally had little adverse effect on employment?

Prior to the introduction of the national minimum wage (NMW) in 1999 there had been no statutory wage floors since the abolishment of the Wages Councils in 1993 by the Conservative government. Growing wage inequality in both the D50:D10 and D90:D50 measure (which looks at the differing wage rates in the respective percentiles) was one of the leading reasons in the demand for some form of minimum wage to counter this growing inequality. Metcalf finds that the NMW reduced the D50:D10 ratio by 9 points if we include the effects of immigration. [...]