The Conservatives have pledged to invest £10bn in a British defence system, if they win the next general election, which is inspired by Israel's Iron Dome air defence system.
The party said the "Britannia Shield" would offer the UK an integrated network of radar, command and control systems, as well as interceptor missiles.
Conservative leader Kemi Badenoch said it would help protect the country against a "new type of warfare" that could see drones and missiles attacking critical national infrastructure.
Defence Secretary Wes Streeting said the Tories had an "abysmal record" of defending Britain during their 14 years in power, adding: "They owe Britain an apology, not another lecture."
The party said the air defence system would be capable of defending the UK's critical national infrastructure, military bases and sovereign territories from sophisticated threats.
Badenoch said that the £10bn would be split over 10 years, with £1bn allocated each year for the project.
Earlier this year, Gen Sir Richard Barrens told MPs on the Commons Defence Select Committee "the cost of an iron dome at entry level is probably £80bn over 10 years".
Although the Conservatives said the system would be "in essence a British 'Iron Dome'", Badenoch appeared to draw back from that comparison in broadcast interviews.
Speaking to the BBC, she said: "We are not building the Iron Dome... We are designing something specific for the kind of threat that we face here."
She said the system would not be "exactly what Israel has" and that the UK needs to start "thinking ahead" to ensure it can protect itself against hostile missiles and drones.
She said she had been listening to figures like Ukrainian President Volodymyr Zelensky and following the impact of the war in Iran on Gulf countries when crafting her plans.
"Warfare is changing," she said. "It isn't just missiles coming from very far afield anymore, what we are seeing with drone technology is that people can get close enough to fire drones at the UK."
The Tories added the proposal would strengthen the UK's air defence systems at a time when Nato allies have warned they are facing repeated Russian drone incursions.
The party also cited a report from the defence committee of MPs last November which said the UK was lagging behind its European counterparts in having a plan to defend itself and overseas territories from a military attack.
The Conservatives said the system would have three components - new advanced radar systems, upgraded command and control systems to integrate information from across Britain's defences and rapidly decide a response, and new interceptor missiles as well as counter-drone capabilities.
The three-tiered design of the proposal is similar to the British Army's current Sky Sabre, external air defence system.
This system - which can intercept munitions and aircraft as well as integrate with wider air defences - was deployed by the UK to the Middle East earlier this year for defensive action against Iranian attacks.
Sidharth Kaushal, a senior fellow at the defence and security think thank RUSI (the Royal United Services Institute), said £10bn would "probably cover" what the UK "actually needs" including horizon radar and more E7 aircrafts.
"In contrast, if what the Conservatives envision is a truly Israeli style multi-layered missile defence system, £10bn probably wouldn't get there," he said.
"But that system would also be quite superfluous, arguably."
Prof Steven Barrett, CEO of Cambridge Aerospace which has been developing interceptor missiles, told the BBC £10bn was a "significant commitment" but the exact cost of the project would depend on the detail of the Conservatives' proposal.
He said that it would not be practical for the system to defend "every square inch" of UK territory and a more plausible set up would cover "significant parts of the population in key high density areas".
He also said there needed to be a focus on protecting critical national infrastructure, adding that a" huge amount of damage" could be done if data centres used by transport and health systems came under attack.
In his speech at the conference in Birmingham, shadow defence secretary James Cartlidge will say: "With a £10bn budget, this would be one of Britain's most significant military programmes since the cold war.
"But one that is totally necessary because of the threats we face."
Streeting said in response: "They [the Conservatives] cut the Army to its smallest size since Napoleon and left a £17bn hole in the equipment plan.
"Their own defence secretary, Ben Wallace, admitted our Armed Forces had been 'hollowed out and underfunded'."
The Conservatives said their plan would be funded within their existing commitment to spend 3% of GDP on defence by 2030, paid for by welfare reform and reprioritisation of existing expenditure.
Prime Minister Andy Burnham has been under pressure to set out how he will reach Nato's 3.5% of GDP spending target by 2035, up from an estimated 2.6% this year.
The current Labour government's Defence Investment Plan includes more than £350m to double the number of Sky Sabre systems operated by the British Army, with ground-based air defence sitting alongside air and maritime capabilities.
