Lawyers said Mr Gove’s new rules could also undermine the common “rights of lights” law, which entitles a property owner to a minimum level of natural light.
Geoffrey Adams, senior director at surveying firm Anstey Horne, said: “A two-storey extension can hugely increase bulk and restrict light into neighbouring properties. That does and will have a legal impact, and most likely a knock-on to people’s health.”
Under the proposed rules, rear extensions would be allowed to reach as high as the highest point of the house – as long as the extension cannot be seen from the street.
L-shape extensions, which wrap around the two sides of a home, could also be allowed without planning permission.
The Government’s consultation says homeowners should be allowed to convert as much of their loft space as they wish, rather than being limited to 50 cubic metres in most cases, or 40 cubic metres in terraced houses.
Those living in flats with loft space will be able to make “modest extensions” without planning permission, under the plans. Current height limits for single-storey extensions will remain at four metres, in order to protect against overdevelopment.
The fine print of the consultation revealed that the Government is seeking to scrap rules that mean that the freeholder of a block of flats can add two storeys on top of the existing building.
Leaseholders have previously complained about the existing rules, saying they do not give them a say in the development of their building.
The government consultation on the proposals is open until April 9.
