They have accused the department of delaying the difficult decisions it needs to make if it is to spend within its means.
Forecasts by the MoD reveal a gap of between £7bn to £14.8bn between what it wants to spend and what it can actually afford in its 2017–27 equipment plan.
According to a report by the Public Accounts Committee published today, even the higher estimate of £14.8bn looks “unlikely and overly optimistic”.
Using the £7bn figure, the MoD estimates that 84% of its affordability gap falls in the first four years of its 10-year plan.
The PAC said it was “alarming” that the department had not yet taken decisions to make the plan more affordable.
Its report noted: “Despite committing to tackle this problem, the department has made little progress, continuing to delay the difficult decisions needed to make the equipment plan affordable, particularly around which programmes to stop, delay or scale back.”
Affordability concerns have led to short-term decision making which has only worsened the longer-term affordability risks, the PAC said.
Meg Hillier, PAC chair, said: “In terms of poor financial planning, the MoD is a repeat offender.
“The department’s progress with addressing the concerns set out in our last report on the defence equipment plan has been woeful.
“A department that is unwilling or unable to take the action required to help it live within its means is failing taxpayers, who rightly expect government to deliver the best possible value for their money.”
A MoD spokesperson said: “We are confident that we will deliver the equipment plan within budget this year, as we did last year, as we strive to ensure our military have the very best ships, aircraft and vehicles.
“At the same time, we are addressing the financial challenges posed by ambitious, complex programmes, after securing a £1.8bn financial boost for defence and reducing forecast costs by £9.5bn through efficiency savings.
