Rishi Sunak has watered down a manifesto commitment to build 300,000 new homes a year in the UK in an effort to stave off a rebellion by Conservative MPs who chiefly represent more prosperous southern constituencies.

The prime minister has faced growing opposition on planning reform between two tribes of MPs from different parts of England. While those representing northern seats are eager to liberalise restrictions, MPs in traditional Tory heartlands wish to avoid what they claim would amount to further excessive building.

Planning reform was also one of the main supply-side reforms that former premiers Boris Johnson and Liz Truss hoped could boost growth. But previous efforts to ease curbs have failed in the face of rebellions by Conservative backbenchers.