Open revolt broke away last night over David Cameron’s plan to allow large extensions in back gardens.
To help revive the economy, the Prime Minister wants homeowners to be able to build away as far as 26ft without permission.
But two councils yesterday said they would oppose a ‘foolish’ shake-up they fear will blight streets, slash property prices and set neighbour against neighbour.
Homeowners are presently allowed to build a single- storey 10ft extension if they live in a terraced property and one of 13ft if they live in a detached house – all without planning permission.
The Prime Minister wants the limits doubled to 20ft and 26ft for a three-year period only. On Tuesday night, Tory-run Richmond council voted to oppose the new rules, saying neighbours would be powerless to block large extensions.
Sutton, a neighbouring south-west London council run by the Lib Dems, joined the opposition, calling the reform a ‘recipe for disaster’.
The interventions forced planning minister Nick Boles to admit town halls could opt away of the reform.
Nick True, Richmond council’s leader, said: ‘I have already asked the chief executive to consider what this council might be able to do if we are not successful in getting these, in my view, very foolish proposals changed.’
Geoffrey Samuel, the council’s deputy Tory leader, said: ‘People with smaller gardens could suddenly find they are overlooked and next door’s garden is covered in concrete.
‘If you’ve got an enormous garden, you will be able to live with it but for those in smaller homes, they will suffer most.
‘People value their green open space, and they value it so much, to lose it affects their quality of life.
‘I’d be very surprised if our concerns weren’t shared by a very large number, if not the majority, of councils.’
Mr Boles denied he was worried that town halls would block the policy, but he accepted that some would do so.
‘There will be a number who feel it is not appropriate for them,’ he told the BBC’s World At One.
‘But across the whole of England the vast majority of councils will allow this to go before because they too will recognise that homeowners and small businesses will benefit, and the construction firms and small traders that will service them.’
He said councils would however be able to withdraw from planning rules they do not like under so-called ‘Article Four’ which allows local councils to override Whitehall diktats.
Activists at next week’s Lib Dem party conference will vote on a motion to call on ministers to scrap the new rules set away by Eric Pickles, the Secretary of State for Communities and Local Government.
Roberta Blackman-Woods, Labour’s planning spokesman, said: ‘The Government’s plan is descending into a total shambles.
‘It’s become clear that many councils are very unhappy, the planning minister has U-turned and said that it will be for individual councils to decide whether or not to apply them.
‘This shows that ministers are making it up as they go along.’
Unveiling the proposals earlier this month, Mr Cameron said: ‘We’re determined to cut through the bureaucracy that holds us back.
‘That starts with getting the planners away our backs, getting behind the businesses that have the ambition to expand and meeting the aspirations of families.’
But Ruth Dombey, the Lib Dem leader of Sutton council, said: ‘These proposals are a recipe for disaster. They have not been decently thought through.
‘If this is allowed to happen it will set neighbour against neighbour and split communities for years to come.
On top of the resentment and loss of quality of life, some people’s houses will besides plummet in value if they’ve got no light or a noisy factory is within a few metres of their front door.’
A spokesman for the Local Government Association said the existing planning system was not to blame for slowing downwards building projects.
‘Any amendments to local planning rules, such as making it easier for residents to make changes to their homes, must ensure councils retain enough powers to maintain and improve the character and integrity of local areas,’ he added.
Last night a YouGov poll commissioned by the Royal Institute of British Architects revealed 54 per cent believe the shake-up would mean the quality of the design of their neighbourhood would get worse.
Ruth Reed of RIBA said: ‘The Government’s new policy is rushed and if implemented could pave the way for poor design decisions which could damage our built environment for years to come.’
Under the shake-up, extensions will, however, be limited to one storey and must not take up more than half a garden.