A radical extension of Margaret Thatcher’s flagship housing policy is set to be included in the Conservative manifesto as Tories bid to woo working-class voters.

The Right to Buy would be extended to up to 2.5million housing-association tenants, transforming the lives of many.

The reform, backed by senior Conservatives including Iain Duncan Smith, Boris Johnson and David Davis, is expected to be included in a ‘big doorstep offer’ on housing from the Tories.

Scroll down for video

The Conservatives are set to include Margaret Thatcher's flagship housing policy in the party manifesto in a bid to woo working-class voters. Pictured, Mrs Thatcher at the Conservative Party Conference in 1989

The party is also considering plans to force councils to sell large, expensive council homes in order to fund higher numbers of cheaper properties.

A Number Ten source said: ‘The Prime Minister has been a big supporter of Right to Buy, so that more people can own a home of their own. But our manifesto will be announced nearer the election.’

Enabling housing-association tenants to buy their homes would likely require major changes to the 1996 Housing Act, forcing associations to sell properties at discounts set by government.

The Coalition has increased Right to Buy discounts, meaning more council homes are already moving to the private sector.

Prime Minister David Cameron (pictured left) is a big supporter of Right to Buy, a Downing Street source said, and the reform is backed by senior Conservatives, including the Mayor of London Boris Johnson (right)

But housing associations have gradually replaced councils as the main providers of social housing. They are autonomous, not-for-profit bodies that provide low-cost homes using public money and loans from the private sector.

Right to Buy, introduced in 1980, led to more than 1.5million council homes being sold at discounted rates.

Senior Tories believe a ‘right to own’ would attract more ‘C2 voters’ – the skilled working classes that helped deliver Lady Thatcher’s election victories. It would promote home ownership as well as drastically reducing the housing benefit bill.

At the moment, taxpayers subsidise the housing costs of many unemployed and lower paid workers who live in properties provided by housing associations.

Current Right to Buy rules let most council tenants buy their homes at a discount. But housing-association tenants have limited discounts and can only buy a property acquired by an association since 1997.

Britain's Secretary for Work and Pensions Iain Duncan Smith set up a think-thank in opposition to rules limiting the discounts housing association tenants can receive under the Right to Buy scheme

The Centre for Social Justice, the think-tank set up by Mr Duncan Smith in opposition, has suggested housing-association tenants should be offered discounts of up to 30 per cent of a property’s value.