Successive Conservative governments have failed to deliver a single new “starter home” despite promising to build 200,000 by 2020, Whitehall’s spending watchdog has found.

The party’s 2015 manifesto committed to building the homes across England to be sold exclusively to first-time buyers under the age of 40, to help young people take their first step on the property ladder.

The National Audit Office (NAO) said that, to date, no such homes have been built because the government has not budgeted for them or activated all of the necessary legislation.

The 2015 spending review set aside £2.3bn to support the delivery of the first 60,000 properties under the scheme.

But the Ministry of Housing, Communities & Local Government (MHCLG) no longer has a budget dedicated to the project, auditors said in a report released on Tuesday.

Funding that had been earmarked for the scheme has instead been spent on acquiring and preparing brownfield sites for housing more generally – some of which was “affordable” housing.

The Housing and Planning Act 2016 created the statutory framework for the project to go ahead, but the NAO said the relevant sections of the legislation had yet to come into force.

The report said, while it was possible developers had built and sold some properties that met the starter home criteria, legally they could not be marketed as such until the MHCLG had put in place the necessary secondary legislation.

Meg Hillier, the chair of the public accounts committee, said: “Despite setting aside over £2bn to build 60,000 new starter homes, none were built.

“Since 2010 many housing programmes announced with much fanfare have fallen away, with money then recycled into the next announcement.

“The department needs to focus on delivery and not raise, and then dash, people’s expectations.”

The shadow housing secretary, John Healey, said: “The Conservatives’ flagship housing announcement for first-time buyers has been a total failure. It’s clear you can’t trust the Tories to do what they promise.”

The report comes as a new coalition of housing organisations has called for all new homes to be made accessible and adaptable.

The organisation, Housing Made for Everyone (HoME), includes Age UK, the Royal Institute of British Architects (Riba), Disability Rights UK, the National Housing Federation, and the Chartered Institute of Housing.

It has published an open letter calling on the next government to take greater action to secure housing suitable for an ageing population and people living with disabilities.

It reads: “Without action, we face an ever-mounting bill, with councils spending greater sums on trying to adapt homes retrospectively and the costs to our health and social care systems spiralling.

“The cost to individuals is no less damaging. Now is the time to ensure that everyone’s right to a safe and accessible home is met, today and in the years to come.”

Anna Dixon, the chief executive at the Centre for Ageing Better, which is part of the coalition, said: “We face a dangerous shortage of homes that are accessible and adaptable.

“Whilst it’s not inevitable, the likelihood is that most of us will experience disability or difficulties with activities of daily living at some point in our later life.

“And with more of us living for longer, this dire lack of accessible homes represents a ticking timebomb.”

An MHCLG spokesperson said: “We are committed to building more homes and supporting people into home ownership. We have a great track record and housebuilding is at its highest level for all but one of the last 30 years – with 222,000 homes delivered last year, and 1.3m in total since 2010, including over 430,000 affordable homes.

“The number of first-time buyers is currently at an 11-year annual high, and over 560,000 households have been helped into home ownership through government schemes like help to buy and right to buy.”