If we adopted this in U.K. cities (turning left on red, of course, not right) it would improve traffic flow, reduce delays and improve business efficiency. It would also save costs, because expensive schemes to add capacity to city roads would not be needed, or at least could be deferred to a later date.
In Canada, and I think in the USA, it is legal to do a right-turn on a red traffic light. This has of course to be done with care. But the result is that traffic flow is increased, especially in heavily built-up areas.
Having lived in Canada for 15 years, I saw this operating without any problem.