This is because of a web of more complex factors: the green belt, shortage of land and credit, and developers sitting on land banks because house prices continue to rise.
"It isn't satisfactory that there is some land banking, where big companies are sitting on land that should be developed for people to have homes," he said.
Miliband will say: "Across our country there are firms sitting on land waiting for it to accumulate in value and not building on it.
"Across our country, there are firms sitting on land, waiting for it to accumulate in value and not building on it.
But what it means for the country is that developers are sitting on land for houses that could be put on the market and relieve the housing shortage.
So the party will examine the need for new statutory powers to charge owners escalating fees for sitting on land with planning permission, to incentivise them to release the land.
Consider what it took to put the pieces together; above all the acquisition of the relevant tracts of land; and then consider that Tesco, the UK's largest supermarket chain, is sitting on land and buildings sufficient to build 15,000 homes.
Others are in trouble, partly because they are sitting on land banks of uncertain value.
Miliband, meanwhile, denied he was digging up old Labour with his plans to stop developers sitting on land.
She told MPs that "we are consulting on proposals to deter developers from seeking planning permission and then sitting on land without bringing forward new homes".
"What about some real radical thinking," Lord True says, "like a right for local councils to require developers sitting on land banks to get on with the job?
