Perhaps not formally, but there is an area of Birmingham - Bordesley Green, occupied by predominantly Asian communities, where front extensions (and some side extensions facing roads) have been built over the years contrary to planning policy and which the council has previously said that it will not do anything about the ones already built or similar development in the future because now that is the style of the various frontages and area generally. Basically a precedent.
Now you might wonder why I mentioned the ethnicity of the community. Well one "excuse" put forward by a local councillor (who would normally be expected to uphold the law and his council's policies, but that's another matter) was that certain races have large families and so need bigger houses - and can't afford to go through the normal procedures.