Boris Johnson’s pledge to build 40 new hospitals by 2030 has hit fresh trouble after being judged “unachievable” by a watchdog.

The project – already dogged by criticism that most schemes are refurbishments, rather than new buildings – has been given a “red” rating by the Infrastructure and Projects Authority (IPA).

It means there are “major issues with project definition, schedule, budget, quality and/or benefits delivery, which at this stage do not appear to be manageable or resolvable”.

Sources told the Health Service Journal that the IPA carried out two reviews of the programme in the last six months, the latest review – completed this autumn – resulting in the “red” rating.

The IPA’s 2020-21 annual report gave it an “amber/red” ranking, which meant the successful delivery of the project was “in doubt”, but the forecast had now worsened.

The department of health and social care acknowledged the “red” rating and has been asked to respond to fears that the pledge – a key part of the 2019 Conservative election campaign – appears doomed.

Labour pointed to the revelation emerging one day after Mr Johnson “sneaked out social care changes” that will force poorer pensioners to pay higher care bills.

“We learn the government’s own Infrastructure and Projects Authority is warning the Tory promise to deliver 40 new hospitals is now ‘unachievable’,” said Jonathan Ashworth, the shadow health secretary.

“From failing to stamp out corruption, betraying the north over rail and now more broken promises over health and care, the Tories simply can’t be trusted to deliver any of their promises.”

The promise of 40 hospitals came under fire almost immediately, when the bill was put at as high as £24bn – while the Tories refused to specify the cost or where the money would come from.

It then emerged that, of the 40 projects, the majority were not in fact new hospitals but were rebuilding projects on existing sites, or the addition of extra units.

Last summer, it was revealed that health bosses had been ordered to ensure that any such building scheme “must always be referred to as a new hospital”.

The instruction was contained within instructions sent to NHS trusts called the New Hospital Programme Communications Playbook, also leaked to HSJ.

Sajid Javid, the health secretary, was embarrassed when he said he was looking forward to opening a “new” hospital – when the cancer care centre had been planned before Mr Johnson’s 2019 pledge.

The HSJ also reported that the Cabinet Office has drafted in a former transport infrastructure chief in Australia to speed up the programme.