The start of a major cross-Government review into British defence, security and foreign policy is a decision for the Prime Minister, a top Ministry of Defence (MOD) official has said.
The Integrated Review, described as the biggest of its kind since the end of the Cold War, was paused in April over the coronavirus pandemic.
The review was due to get underway at the end of the year but is now not expected to start until 2021.
In a meeting with MPs on the Public Accounts Committee on Thursday, the MOD's Permanent Secretary was asked when he expects the review to begin.
Sir Geoffrey Clifton-Brown said: "That is not a decision for me, it's a decision for the Prime Minister.
"The indications that we have been given are that the full Integrated Review will be some time next year."
He added the defence review, although delayed, still must go ahead.
Sir Geoffrey also faced questions over the MOD's procurement plans.
The MOD's accounts have bee under scrutiny for years, with its defence equipment plan repeatedly found to be unaffordable.
MPs on the committee asked Sir Geoffrey whether there were plans to make cuts.
He said it would be "quite easy" to make cuts if needed but there were also warnings of making savings too quickly.
The procurement of Britain's F-35B fighter jets was used as an example.
In 2010, a decision was made to swap the vertical take-off jets to a conventional take-off variant, only to revert back to the original plan because of the costs.
Air Marshal Richard Knighton, Deputy Chief of the Defence Staff, said: "What happened with the F-35 and the carriers was that [the decision] it was made rather quickly, with inappropriate levels of evidence.
"I think that we need to be very careful and thoughtful about making a similar mistake again in any kind of review where the pressure is on to make quick decisions potentially to make savings."
The procurement process fo the Armed Forces is set to be a focus point of the upcoming review.
Tobias Ellwood, Chairman of the Commons Defence Select Committee, said the review should consider the "consequences of the pandemic".
The review is also expected to look at ways to develop the military's capabilities.