The Prime Minister has indicated that defence spending will be protected from cuts as the Government tries to balance its books during the COVID-19 pandemic.
Appearing before the House of Commons Liaison Committee on Wednesday, Boris Johnson said "we do not resile" from the commitment to increase defence spending at least 0.5% above inflation.
It is one of two 'locks' the Government has offered to protect the Ministry of Defence (MOD) budget for several years now.
However, with an Integrated Review of Defence and Foreign Policy under way, while the Government is spending hundreds of billions of pounds on the fallout from coronavirus, concerns have grown that at least one of those locks might be abandoned to make savings from defence.
The chairman of the Commons Defence Committee, Tobias Ellwood, told the PM that the NATO commitment, to spend 2% of national income (GDP) on defence, was insufficient.
"That means little because of the pandemic, and the effect on the economy," he said.
The UK's GDP is expected to fall by 10% this year, meaning the UK could significantly cut defence spending and still meet its NATO commitment.
But the PM's response to Mr Ellwood, while not a direct commitment, strongly suggests that in real terms, the defence budget will continue to grow at least a little.
"We are increasing our defence budget by 2.6%, above inflation - 2019, 2020, 2021," he said.
"We’ve made the point-five commitment from which we do not resile."
If, as seems to be the case, both 'locks' remain in place it would mean the Integrated Review is being carried out with defence spending expected to stay on a fairly stable trajectory for the next few years.
Mr Johnson also told the committee that the Government-wide Integrated Review, launched earlier this year by the Prime Minister, would provide an opportunity to "change the world for the better".
It has previously been described as the deepest review of British foreign, defence and security policy "since the Cold War" by Mr Johnson.
"We will be setting out a wholesale analysis of where the UK sees its opportunities but also its responsibilities and I don’t want to summarise it or to caricature it now," he told Mr Ellwood.
"But it is an opportunity for the UK, for us to protect our values overseas, to change the world for the better in the way that we have been describing, to create as it were, to open up opportunities for the UK around the world as well.
"The animating principle will be not just the need to project UK ideas and UK values but also opportunities for jobs and growth here in the UK."