In September the government unveiled the proposals, currently out for consultation, to relax planning rules for a three-year period to allow home owners and businesses to build larger extensions to their properties without the need for planning permission.
The move was widely criticised by local authorities and others who claimed it would damage the look of neighbourhoods and cause friction between neighbours.
The consultation document into the plans said the move would save householders money and help local construction firms.
It said: "These measures will bring extra work for local construction companies and small traders, as families and businesses who were previously deterred take forward their plans. For illustration, 20,000 new extensions could generate up to £600 million of construction output, supporting up to 18,000 jobs. In addition, each family who benefits will save up to £2,500 in planning and professional fees, with total savings of up to £100 million a year".
But the report into the proposed changes, by the communities and local government select committee, said the assumptions on the financial benefits of the plans outlined in the government’s impact assessment, which was published alongside the consultation document, were "so tentative, broad-brush and qualified as to provide little assurance that the financial benefits suggested will be achieved".
The report said the government's estimated range for the possible savings to applicants, of between £5 million and £100 million annually, was "so wide that it does not provide a sound basis for the change. If the realised savings are at the bottom end of the range, there must be a question of whether the changes are worth the disruption".
Elsewhere, the committee found that the government had failed to address or evaluate the social and environmental arguments put forward against the proposed changes. It said: "The justification for the changes is framed almost exclusively in terms of economic considerations. We found little or no evidence that the government had considered or addressed the social or environmental impact of the changes".
"Its approach has therefore disregarded two of the components of sustainable development as set out in its own National Planning Policy Framework".
The report said that if, against the committee’s views, the government "persists with its proposals", a number of changes should be made. They are:
- Because of the potential impact on areas with a significant number of houses in multiple occupation, there is a strong case for excluding them from the relaxation at least until a thorough impact assessment has been carried out.
- Second, if Article 4 directions, which enable local planning authorities to limit the effect of permitted development rights, are to provide a viable local exemption from permitted development rights, the report says it would be necessary to remove any payment of compensation to affected property owners and to allow local authorities to charge for planning applications falling within Article 4 in cases such as domestic extensions.
- The government should carry out a review of the impact of the changes at the end of the three year "trial". It recommended (a) that the review includes an independent study, including commissioned research on neighbour disputes and the impact on the quality, design and amenity of the permitted development and on the local area and (b) an invitation to interested parties to submit evidence and (c) that the outcome of the review be published.
Committee chair Clive Betts said: "The effects of this temporary relaxation of the planning rules will be new development which will have a permanent effect on neighbours and localities. I am uneasy that the proposed change will therefore be temporary in any manner. If a change to the planning rules is justified, it should be permanent. If it is not justified, it should not be made. The government needs to go back to the drawing board."
Response to government's consultation on permitted development rights for homeowners can be read here.