Video report by ITV News Political Correspondent Carl Dinnen
Theresa May has announced plans to reform planning rules to get developers building more houses to address the shortage of affordable homes.
During a speech in London, the prime minister said unaffordable housing in England is creating a crisis of "almost literal social immobility".
"In much of the country, housing is so unaffordable that millions of people who would reasonably expect to buy their own home are unable to do so."
The prime minister added that the crisis has led to a "vicious circle from which most people can only escape with help from the Bank of Mum and Dad".
Mrs May also insisted she "cannot bring about the kind of society I want to see, unless we tackle one of the biggest barriers to social mobility we face".
She also warned developers their past record could count against them when they bid with councils for new planning permissions.
"I want to see planning permissions going to people who are actually going to build houses, not just sit on land and watch its value rise," Mrs May said.
Writing in the Daily Telegraph ahead of the speech at a national planning conference, Mrs May took aim at housebuilders constructing "row after row of identikit red-tiled boxes" in towns and cities with the plans putting a focus on buildings which suit their surroundings.
The prime minister has also pledged take on the "perverse incentive" where "the bonuses paid to the heads of some of our biggest developers are based not on the number of homes they build but on their profits or share price".
Mrs May also announced a nationwide standard that sets out how many homes councils need to plan for in their area.
Rules will be made clearer to show councils they can prioritise affordable homes for "key workers" including nurses, teachers and firefighters.
Labour's shadow secretary of state for housing, John Healey MP, said: "The Prime Minister should be embarrassed to be fronting up these feeble measures first announced a year ago.
"After eight years of failure on housing it's clear her Government has got no plan to fix the housing crisis."
"This housing crisis is made in Downing Street. It's time the Tories changed course, and backed Labour's long-term plan to build the genuinely affordable homes the country needs."