The "fire sale" of publicly-owned land is making the housing crisis worse, with affordable homes making up just one-in-five of those built on the sites, a think tank has warned.
The analysis found that 20% of new homes would be classed as affordable, with some developments made up entirely of luxury properties.
The New Economics Foundation (NEF) research found as little as 7% of homes built on the sold-off land would be social housing and the pace of construction also fell well short of Government targets.
The analysis indicates that at the current rate, the target of building 160,000 homes by selling off public land will take until 2032, 12 years later than promised.
The think tank called for Chancellor Philip Hammond to cancel the sell-off in the Budget on March 8.
NEF housing lead Alice Martin said: "The Government's fire sale of public land is failing by its own measure and making the housing crisis worse.
"This irresponsible approach is bringing to market a slow trickle of property that few can afford.
"Every day, people are finding it harder and harder to find an affordable place to live.
"Next week the Chancellor could help people take real control over their lives by putting an end to this land sell-off.
"Public land should be put to public use.
"The Budget is a chance for the Government to empower communities so they can help build the good quality, affordable homes we so desperately need."
The NEF suggested that by halting the sale of public land, the Government could allow for community-led housing projects, backed by councils, small builders and institutional investors such as pension funds.
The think tank's analysis was based on the development plans for public land sold off in the first half of 2016/17.
A Department for Communities and Local Government spokesman said: "We're clear that we need to fix the broken housing market so that homes are more affordable. Increasing the supply of land for housing is a vital part of this.
"By the end of September 2016, Government had already sold or identified public sector land to make way for 145,492 new homes.
"This is 90% of the land to meet our commitment for 160,000 homes by the end of the Parliament. Plus we're investing £1.4 billion to create more affordable housing."