The policy, which was floated in the press earlier this year, would see up to 1.3 million families in England who are housing association tenants gain the right to buy their home at a significant discount, in the same way as council house tenants.

The expansion of Right to Buy to include more housing association tenants has won the support of some Labour Party politicians in the past, including former welfare minister Frank Field and former cabinet minister Alan Milburn.

David Orr, chief executive of the National Housing Federation, previously attacked moves to sell social housing in “high value” areas, saying it “could effectively cleanse many towns of hard-working people who simply can’t afford the high prices of buying or renting privately”.

The Federation’s director of policy and external affairs, Ruth Davison, said: “We fully support the aspiration of homeownership but extending Right to Buy to housing associations is the wrong solution to our housing crisis. Following 40 years of successive governments’ failure to build the homes the country needs, soaring rents and house prices and the biggest baby boom since the 1950s, ensuring that there enough homes today and tomorrow must be our nation’s top priority.”

As he launched his party’s manifesto in Swindon, prime minister David Cameron (pictured) said his party’s proposal to “radically expand one of the Conservative Party’s landmark ideas” showed that “the dream of a property-owning democracy is alive”.

Cameron said: “Part of having a good life is having a home of your own. It’s not about ‘assets’ and ‘appreciating values’ – it’s about someone standing there with their keys in their hand thinking ‘this place is mine.’”

He said that expanding Right to Buy to an extra 1.3 million families would see “a whole new generation given the security of a home”.

Gavin Smart, deputy chief executive of the Chartered Institute of Housing (CIH) joined other figures from the social housing sector in criticising the plans.

Smart said: “Extending right to buy to housing associations is not going to tackle the housing crisis - in fact it could make things worse for people on lower incomes who are already struggling to access a decent home at a price they can afford.

“Individual tenants might benefit from the opportunity to own a home, but we would be very concerned that it would result in a dramatic loss of vital social and affordable housing. The Conservatives say that forcing councils to sell off their most valuable properties would fund this extension plus 400,000 new homes over five years - we fear the figures simply won’t stack up.

“And it could have a huge impact on councils’ ability to build new homes, particularly in more expensive areas like London and the south east, where it might actually make more sense for them to borrow against the value of these properties so they can fund more homes.”

The extension of Right to Buy in England is in stark contrast to housing policy in Scotland, where the devolved Scottish Parliament voted to end Right to Buy for all council and housing association tenants in Scotland from 1 August 2016.

At the time, Scottish housing minister Margaret Burgess said: “With 185,000 people on waiting lists for council and housing association houses, we can no longer afford to see the social sector lose out on badly needed homes.”