The Defence Secretary has indicated he is looking at the size of the UK Armed Forces in light of the Russian invasion of Ukraine.
Ben Wallace addressed the Defence Committee as he answered questions on the Ministry of Defence budget.
The Prime Minister, who attended a NATO summit last week, has promised an additional £55bn in defence spending over the rest of the decade in response to the threat posed by Vladimir Putin's Russia.
Boris Johnson committed Britain to increasing defence spending to 2.5% of gross domestic product (GDP), a measure of the size of the economy, by the end of the decade.
The Prime Minister’s pledge followed lobbying from Mr Wallace and Foreign Secretary Liz Truss.
Mr Wallace told the Defence Committee the Army currently has 81,000 regular personnel, with a plan to cut that to 73,000 in coming years.
The Defence Secretary, who presented a united front with the Prime Minister on the issue, said: "If the decision was to be made to increase the size of the Army, if the decision was to be made, do not be surprised if it is not in the cavalry or the infantry.
"It is quite interesting how attached people are to platforms."
Mr Wallace stressed that the Ukrainian conflict outlined how investment is needed in electronic warfare and air defence, which he described as "deeply inadequate".
Watch: Troop numbers are kept under 'constant review', says Prime Minister.
On the defence budget, he added: "I have made it perfectly clear that… before Russia invaded Ukraine, we took a decision that there would be a dip, sort of a sunset and sunrise, in capabilities.
"The threat has changed, so I take a view that some of those areas we were prepared to take a risk in are areas we should not be prepared to take that risk, and therefore have I made no secret of the fact that that is a place we would look for more money or more investment."
When questioned about how the UK would be ready for any potential confrontation with Russia, Mr Wallace hinted that the country would rely on the NATO alliance.
He added that Britain would benefit from Finland and Sweden's membership.
Mr Wallace said everything he does is based around ensuring the UK is ready for war.
"In this world, which is more global than ever, you never know where it'll come from," he said.
It comes after Boris Johnson told the House of Commons troop numbers are kept under "constant review" should the situation in Ukraine continue to change.
The Prime Minister was responding to a question from Conservative MP and British Army veteran Johnny Mercer.