Integrated Review

[4][7] Johnson's successor, Liz Truss initiated an update of the Integrated Review due to evolving threats, particularly Russia following its invasion of Ukraine.

[15] Prime Minister Boris Johnson claimed it was "the biggest review of our foreign, defence, security and development policy since the end of the Cold War.

"[15] In a statement in September 2020, Prime Minister Boris Johnson confirmed the Integrated Review would be underpinned by a commitment to spend at least 2% of GDP on defence—as defined as a target by NATO, 0.7% of GNI on Official development assistance and the maintenance of the British nuclear deterrent.

He explained that this would entail being forward deployed — for example, in Europe to deter Russian activity, in the Middle East to combat terrorism or in the Asia-Pacific to counter China — and relying on technology to deliver "speed, readiness and resilience" instead of "mass and mobilisation", including in the domains of space, cyberspace and sub-sea.

Reported as the "largest military investment in 30 years", Johnson stated: "This is our chance to end the era of retreat, transform our Armed Forces, bolster our global influence, unite and level up our country, pioneer new technology and defend our people and way of life".

[31] Jack Watling of the Royal United Services Institute stated that the review had "much to commend", due to its well-evidenced judgments and accurate descriptions of the UK's interests but added that it was "fundamentally incomplete".

[37] Leader of the Opposition Sir Keir Starmer also accused the Prime Minister of breaking an election pledge to not cut the number of British Army personnel.

[40] Over a year since its original publication, in September 2022, the newly-incumbent Prime Minister Liz Truss announced that the Integrated Review would be updated to ensure it is "keeping pace" with evolving threats posted by hostile nations, especially Russia in the wake of its invasion of Ukraine.

[41] However, Truss' successor, Prime Minister Rishi Sunak, who took office that October, refused to confirm he would uphold this promise due to economic uncertainty.

He also stressed that China remained a challenge due to the increasingly aggressive military and economic behaviour of the Chinese Communist Party, especially towards Taiwan and Lithuania.