Completely made up number, the point was that 100% of your wage comes from taxation so it costs them nothing in taxes to not pay it. All of that "lost" tax revenue they gain from you they save by not paying you in the first place and then some.
They'll still have to pay benefits, which aren't any cheaper than what most low paid public sector workers earn once you factor in housing benefit etc.
Lets face it, it's not the managers who'll lose their jobs but the cleaners, porters and other low paid staff. That's after all of the private contractors obviously.

