The return of Donald Trump to the White House coincides with a markedly stronger China, a shift that British intelligence and diplomatic sources have described as a fundamental reordering of global power. The assessment, circulated among Whitehall departments this week, concludes that the window for the United States to maintain its unipolar dominance has passed.

The Prime Minister’s office has declined to comment on the specific intelligence, but senior officials have acknowledged that the strategic landscape has been reshaped by China’s rapid military modernisation, its dominance in critical supply chains, and its expanding diplomatic influence across the Global South. The report, authored by the Joint Intelligence Committee, emphasises that this is not a temporary fluctuation but a structural change in international relations.

Mr Trump’s victory has been met with caution in Beijing, where state media have framed his return as an opportunity for transactional diplomacy. Chinese diplomats have already signalled a willingness to negotiate on trade imbalances, but only from a position of strengthened leverage. The Chinese economy, despite its recent slowdown, remains the world’s second largest and is projected to overtake the United States in nominal GDP within a decade.

The British report identifies three areas where China’s relative power has increased since Mr Trump’s previous term. First, its naval capabilities have expanded significantly, with a fleet now larger than the United States’ in terms of hull numbers. Second, its control over rare earth minerals and semiconductor supply chains has deepened, giving it critical economic leverage. Third, its diplomatic outreach, particularly through the Belt and Road Initiative and the BRICS grouping, has eroded the traditional Western consensus on global governance.

A senior diplomat, speaking on condition of anonymity, said: “The United States is no longer the undisputed hegemon. We are living in a multipolar world, and the challenge for the new administration will be managing that reality without triggering conflict.” The assessment notes that Mr Trump’s approach to China is unpredictable, but his reliance on tariffs and bilateral deals may be less effective now that Beijing has diversified its trade relationships.

The British government has urged the incoming administration to coordinate closely on issues such as technology transfer, intellectual property, and maritime security. However, Whitehall sources acknowledge that Mr Trump’s transactional style and his scepticism of multilateral institutions could complicate such efforts.

The report concludes with a warning: the superpower shift is not a future possibility but a present fact. Britain, it argues, must recalibrate its own foreign policy to navigate a world in which the United States is no longer the automatic guarantor of global stability. This will require deeper engagement with European allies, a more independent defence posture, and a pragmatic relationship with China that balances economic interests with security concerns.

For now, the focus is on the transition. Mr Trump’s team has yet to outline a comprehensive Asia strategy, but early signals suggest a continuation of the hardline trade policies of his first term, combined with a possible reduction in military commitments abroad. That combination, the British assessment warns, could accelerate the very shift it seeks to prevent.