A flagship Tory council is opposing the coalition’s plan to allow householders to build larger extensions without the need for planning permission, warning that the measure would be ‘permanently damaging to our built environment’.

Earlier this month, the government unveiled plans to relax for three years permitted development rights for extensions to homes and business premises in non-protected areas.

Communities secretary Eric Pickles told MPs that that the change would extend the existing policy of allowing a domestic extension of three metres to allowing one of roughly six metres, “provided it does not extend beyond half the garden”.

The move was part of a package of measure to boost the economy unveiled by Prime Minister David Cameron. He was widely reported as saying that the proposals would “get the planners off our backs”.

But the leader of the Conservative-led London Borough of Richmond upon Thames in south-west London has expressed his opposition to the proposal and has asked officers to consider ways to circumvent the measure if it goes ahead.

At a council meeting earlier this week, Richmond Council leader Lord True and cabinet member for planning Virginia Morris supported a motion from Lib Dem councillor Martin Elengorn, who had called on the council to resist the measure.

Morris told the meeting that the changes proposed by the coalition government “are against our own planning needs and wants”.

She said: “We’re not against lifting bureaucracy, but we are against conducting measures that will be permanently damaging to our built environment.”

Morris said that the council would bid to “stop” the proposal by writing to the government to explain why it opposes the measure. She added that the council would ask Twickenham MP and business secretary Vince Cable to “call a stop to these measures”.

Lord True said: “I have already asked the chief executive with officers 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.”