Inflation-busting increases will be allocated to defence spending for the next five years, Theresa May has announced.
The Prime Minister declared she will "always put Britain's national security first" as she renewed the Tory pledge to spend 2% of national income on the budget.
It comes after the government faced criticism from retired generals over its military funding.
Mrs May insisted she would ensure "brave" troops were given the cash they needed and claimed Labour's Jeremy Corbyn would put defences "at risk". She said:
"As Prime Minister I always have and always will put Britain's national security first. That is why if elected on June 8 I will ensure that the UK continues to spend at least 2% of GDP on defence and that the budget rises every year."
"Under my leadership the Conservatives will ensure that the brave men and women of our Armed Forces have the equipment and resources they need to keep our country safe - and that we meet our obligations to the world.
"But a strong military is only possible with a strong economy, and Jeremy Corbyn would put both at risk if he makes it to Downing Street propped up by the Lib Dems and SNP in a coalition of chaos.
"Only a vote for me and my Conservative team will deliver the strong and stable leadership that is vital for our national security."
Mrs May announced she was extending by two years a pledge made under predecessor David Cameron to increase the defence budget by at least 0.5% above inflation annually as well as continuing to meet the NATO 2% target.
Nia Griffith, Labour's Shadow Defence Secretary, said:
"The Tories' hypocrisy on defence knows no bounds. Their cuts have left our forces more under-resourced and underpaid than at any time in the modern era.
"The severe cuts imposed on the defence budget since 2010 have seen the Army shrink to 78,000, its smallest size since the Napoleonic Wars and far short of the last Tory manifesto pledge to keep it above 82,000."
"Countless knee-jerk decisions have weakened Britain's defence capabilities, including scrapping our Nimrod maritime patrol aircraft, leaving us reliant on allies to track Russian submarines off the British coast.
"Labour is committed to spending at least 2% of GDP on defence and ensuring that our Armed Forces have the necessary capabilities to fulfil the full range of our NATO obligations, and we will continue to press other members of the alliance to do the same.
"Clearly the Tories care more about a day of positive headlines and cheap rhetoric than the safety of our troops."
Former Liberal Democrat leader Lord Ashdown, who served in the Royal Marines and Special Boat Service (SBS), said:
"This Conservative government has slashed funding on defence, cut our Royal Marines and left our troops on the front line without basic equipment."
Professor Malcolm Chalmers, deputy director of defence think tank the Royal United Services Institute said:
"The extension of the annual 0.5% commitment for another two years is significant, not least because it protects defence to some extent from the uncertainty about the impact of Brexit on government finances overall - and the possibility that a new spending review might require further cuts."
"It should mean that defence will broadly maintain its current share of government spending.
"But an annual 0.5% increase will not be enough to avoid some hard choices on defence priorities."
It follows claims by a series of retired senior military figures that the Ministry of Defence (MoD) was guilty of "accounting deception" in meeting the 2% spending level.
A letter signed by retired admirals, generals and air marshals, as well as wounded war heroes and leading academics, said security is threatened "in almost every corner of the globe", from "nuclear sabre-rattling over Crimea" to uncertainty over the future of NATO.
"The 2015 Strategic Defence & Security Review charted a path towards our future security," it said.
"But the necessary funding is simply not there to give it substance.
"Responses by the MoD to questions about the defence budget have been disingenuous, quoting irrelevant financial statistics."
It added: "Government boasts of spending 2% of GDP on defence are widely criticised as an accounting deception.
"Most analysts agree core defence expenditure for hard military power is well below 2%."