The Tories say they support working people, so they should push this through. My only slight concern is that smaller employers may feel they can't afford the higher wages and so offer fewer jobs. But this was said about the minimum wage, and no problems were encountered when it was put in place.
It's a perfect way to reduce the Welfare bill, as there would be no need for Tax Credits. No chance of them actually doing it though, because it's too much like Socialism.