The Ministry of Defence’s system of procurement is “broken” and is repeatedly wasting billions in taxpayers’ money, according to a scathing assessment by a watchdog committee of MPs.

The Public Accounts Committee (PAC) said that the oversight in the department was so poor that it was unable to spell out what additional capability the country will get from an extra GBP16.5bn which was allocated by Boris Johnson last year.

Of the current 20 largest projects, 13 were running behind, by a cumulative total of 21 years – including the GBP4bn-plus Ajax armoured vehicle, delayed due to excessive noise and vibration. There is “no timescale” when it will be ready for service.

No firm figure was put on the amount of money lost, but the MPs said there had been “wastage of taxpayers’ money running into the billions” and that the MoD at times “lacks the skilled personnel” to manage its suppliers. “The department’s system for delivering major equipment capabilities is broken,” the committee added.

Dame Meg Hillier, the Labour chair of the committee, said: “This committee is determined that this state of affairs cannot, and will not, continue” – and demanded that the Treasury conduct an emergency review of MoD project management.

The senior MP said that PAC members feared that “last year’s lauded and substantial uplift” of GBP16.5bn over four years would “simply be used to plug financial holes across its programmes” because the MoD could not give assurances to the contrary.

The prime minister announced the extra capital spending nearly a year ago, promising it would lead to “a once-in-a-generation modernisation of our armed forces” – including the introduction of laser weapons.

But at the time the MoD also faced a GBP13bn shortfall in its equipment budget, stemming from historic overspending, which had forced it to reduce the numbers of new Challenger 3 tanks, P-8 submarine hunting maritime patrol aircraft and Type 26 frigates.

A total of GBP4bn had already been spent on the heavily delayed Ajax out of “whole life costs of GBP5.5bn,” the committee noted, yet only 14 vehicles – 2% of the total requirement – had been delivered by contractor General Dynamics for testing.

One year ago, the MoD thought Ajax would initially enter service in the summer of 2021 – but this date was not met and the issues over vibration and noise are so serious that 310 service personnel were undergoing tests to see if their hearing had been permanently damaged.

The noise and vibration problems dated back to December 2018 but the MPs voiced concern that the MoD was still in the dark about the cause. “Despite the length of time the department has known about this issue, there is still no definitive information on the source of the noise and vibration,” the PAC said.

Eight programmes were rated either “amber/red or red” by senior officials responsible for delivering them on a traffic light scheme used across government for rating the progress of major procurement projects.

Of broader concern, the PAC said, was the MoD’s apparent inability to learn from its mistakes despite 13 formal reviews of defence procurement over 35 years.

“We were therefore shocked to learn that the department had only established a central register of learning from experience (LFE) in December 2020,” the MPs added. “Experience shows that there is a need for reflection and openness earlier in the process to avoid further catastrophes like Ajax.”

The MoD frequently cited the complexity of the programmes to explain why they had fallen behind, but sceptical MPs said this was not the case. Such arguments aimed to “excuse the fact” that the MoD and its suppliers “failed to produce more realistic costings and schedules”, the committee concluded.

An MoD spokesperson said: “This report reflects the complex challenges of delivering defence capability for our armed forces, but also the commitment and professionalism required to keep our people and the UK’s interests safe, by purchasing world-class equipment such as Lightning II stealth fighter jets, and the Queen Elizabeth aircraft carriers.”