Defence needs more money because the "threat has gone up", according to the Defence Secretary.
Ben Wallace said in an interview that he is "threat-led" and warned that, without a guarantee of significant new funding, overall defence spending was forecast to fall below a core NATO target of 2% of national income by the second half of the decade.
In an interview with Sky News, Mr Wallace highlighted that, at present, UK defence spending is 2.28% of national income "and falling".
Mr Wallace has yet to say publicly whether he is backing Liz Truss or Rishi Sunak in the Conservative leadership contest – both have offered different responses to defence spending.
The Defence Secretary is going to "see what happens in the debates" he told Sky News. He said he will be specifically "interested in what they are going to say on defence."
Foreign Secretary Liz Truss has said she would increase defence spending to 3% of gross domestic product (GDP) by the end of the decade.
Whereas Mr Sunak believes in maintaining the current level of defence spending, refusing to commit to the "arbitrary targets". But he has stated that 2% of the GDP NATO target is a "floor, not a ceiling".
The Defence Secretary has always been clear that, as the threat changes, so should defence spending.
Watch: Ben Wallace visits Ukrainian troops training in UK.
Impact on Forces' capabilities
Mr Wallace said that with an increase in defence spending – up to 3% of GDP by 2030 – certain equipment programmes would probably be bought faster for the Army, Royal Navy and Royal Air Force.
Additionally, the Defence Secretary noted that the Army would carry out a review of what lessons can be drawn from Russia's invasion of Ukraine, addressing any vulnerabilities in the UK defence that would need fixing.
According to reports, this could include a requirement for more long-range artillery systems.
"I think you would see an increase in the numbers of the Army, but not necessarily where people think," Mr Wallace said, noting that all military mass has to be "relevant".
He said the lessons from Ukraine are that "you are better off having small, but perfectly formed, armoured infantry units… than you are having lots and lots of vehicles with none of those protections because they just get killed on a modern battlefield."