David Cameron has been warned his plans to extend Right to Buy will add to the country's housing shortage

The proposal – to extend big discounts to buy their homes to 1.3m housing association tenants – was sharply criticised by housing experts and charities.

And ministers were pressed on whether the funding stream, from forcing councils to sell their expensive homes, would run dry.

Unveiling the Conservative manifesto, the prime minister said: “We are the party of the working people offering you security at every stage of your life.

“We have drawn on all the resources of our nation to turn a great recession into a great recovery. The next five years are about turning the good news in our economy into a good life for you and your family.”

The manifesto offered two other flagship new policies:

•  A doubling of free childcare for three and four-year-olds to 30 hours a week, to be funded from a squeeze on pension tax relief for the rich.
•  Legislation to ensure workers on the minimum wage pay no income tax – although only those who work for no more than 30 hours a week.

After criticism that the Tory campaign has been too negative, Mr Cameron struck a noticeably upbeat tone, referring no fewer than ten times to the “good life”.

However, most focus was on the Right to Buy extension – once rejected by Margaret Thatcher – but with warnings the promise to replace the homes was empty.

It will be funded by forcing local authorities to sell off properties that rank among the most expensive third of that type in their area – raising £4.5bn a year, the Tories said.

But, under existing Right to Buy, 258 homes have been sold off in Southampton, yet work has yet to start on a single replacement property, the Daily Echo previously revealed.

Gavin Smart, of the Chartered Institute of Housing, said: “We would be very concerned that it would result in a dramatic loss of vital social and affordable housing.”

And Crisis, the homelessness charity, said: “It will mean a further decline in our already dwindling supply of affordable housing. This is not the way to tackle the housing crisis – we need more affordable housing not less.”

The Pre-school Learning Alliance questioned whether the promise of additional free childcare could be met, warning the existing 15 hours had not been fully funded.

COMMENT by Rob Merrick

SO, are the “red lights flashing”, David Cameron was asked at his manifesto launch – or are we cruising to the “sunlit uplands”?

The question effectively nailed the screeching U-turn the prime minister was performing on his party’s election campaign, from sombre to chipper in one swift costume change.

Only a few months ago, the prime minister told us “red warning lights are flashing” on the economy and his campaign has pointed to a long hard slog back to prosperity.

Now, the Tories were evoking sunny memories of Jerry and Margo enjoying ‘The Good Life’ in 1970s Surbiton – as he name-checked the title of that much-loved sitcom no fewer than 11 times.

Gone were dour mentions of the ‘Long Term Economic Plan’ in favour of voter-friendly – and expensive – promises on housing, childcare, tax cuts and the rest.

There is no doubt it is the U-turn that Conservative candidates across the land have been crying out for and will be delighted to take back to the doorstep.

The iron grip exerted by Lynton Crosby, the prime minister’s chief strategist – and architect of the narrow, negative campaign – has provoked growing resentment.

After today, Tory candidates in marginal seats will be more confident they have a message that can inspire wavering voters, particularly young families, to stick with their party.

The Right to Buy extension, in particular, got a collective raspberry from the experts, but its overall impact may not worry tenants effectively being offered free money to own their homes.

But the downside of this extraordinary political cross-dressing – making the Tories suddenly the big-spending party – is that Mr Cameron loses credibility as the trusted option.

The prime minister is now promising ‘The Good Life’, but his Chancellor is planning massive spending cuts after polling day, even more severe than we have seen so far.

What about voters not living the good life, or fearing those cuts will make their lives worse? Will the Tories seem out of touch?

Most strikingly, we now know the ins-and-outs of complicated housing policy…but we still have no clue where most of £12bn of welfare cuts will strike?

As another questioner put it: “Why are you telling us about the nice stuff, but not the nasty stuff?”