Labour has announced plans to build on the "grey belt", as it tries to meet its pledge for 1.5 million new homes over the next five years.
Chancellor Rachel Reeves said an overhaul of planning rules would see councils in England expected to prioritise building on brownfield sites and poor quality areas in the green belt.
What is the 'grey belt'?
Labour has previously described the grey belt as "poor quality and ugly areas" - including disused car parks and wasteland - on parts of protected land, called the green belt.
The green belt, which was established more than 70 years ago, covers about 13% of England. Its aim was to limit the growth of large built-up areas and to stop large towns merging into one another.
Labour wants grey belt land to be used for new homes, with half to be affordable housing.