British pharmaceutical exports were not included in the most recent tariff schedule released by the US Trade Representative this week, which imposed levies ranging from 10 to 12.5% on commodities from over 80 nations under Section 301 of the Trade Act. That omission was not an accident, nor was it much of a surprise. It was the visible edge of a deal struck in December, one that has already cost the NHS a great deal more than most patients realise.

The mechanics of the new tariffs are straightforward enough. They replace a 10 per cent global surcharge that Donald Trump imposed under a different legal authority after the Supreme Court ruled in February that his earlier tariff regime exceeded presidential power. This time, the order's annexe expressly excludes pharmaceutical products from its purview, and the rationale is compelled labour enforcement as opposed to emergency economic powers. That exclusion was a comfort to an industry that watched every new announcement from Washington with a sense of impending doom. It is not to be taken as a guarantee.

The reason UK medicines were spared has nothing to do with this week's investigation and everything to do with an agreement signed by Keir Starmer's government eight months ago, under which the United States agreed to keep tariffs on UK-origin pharmaceuticals and medical technology at zero for the remainder of Trump's term. In exchange, the NHS committed to raising its National Institute for Health and Care Excellence cost-effectiveness threshold, cutting the rebate rate that drug companies pay back under the Voluntary Scheme for Branded Medicines from around 23 per cent to 15 per cent, and doubling medicines spending as a share of GDP over the next decade. This month's analysis published estimated that by 2036, the arrangement would cost over £45 billion that would have been redirected from other NHS services. Researchers projected that this would result in well over 200,000 preventable deaths as a result of funding shifting from frontline treatment to the expense of new medications.

That figure has been disputed by ministers, who point out that patients gain access to treatments previously rejected on cost grounds, including cancer therapies and rare disease drugs that would otherwise never have reached NICE approval. Both things can be true. By allocating billions of pounds of future spending to an administration whose tariff policy has already been overturned once by its own Supreme Court and is still facing legal challenges from trade economists who believe the current approach is unconstitutional, the NHS bought assurance for its exporters and improved access for some patients.

This is where the real story sits, several layers beneath the headline tariff numbers. A trade protection that depends on the discretion of one president, renewable only through his continued goodwill and reviewable every time his administration launches a new investigation, is not the kind of foundation on which a health system should be building a decade of spending commitments. The December deal can be terminated by either side with six months' notice. A parallel Section 232 tariff of 100 per cent on patented pharmaceuticals is due to take effect for most manufacturers by late September, and the UK's exemption from it rests on the same fragile understanding that just held for the forced labour tariffs. Nothing legally prevents Washington from revisiting either exemption the next time it wants leverage in some unrelated dispute.

For NHS finance directors and life sciences investors, the practical lesson is that this week's non-event was still a live demonstration of exposure. Every fresh round of American trade action is now, in effect, a test of an arrangement the health service has already paid heavily to secure and cannot itself enforce. Ministers have chosen certainty for exporters over control of the NHS budget line. Whether that trade continues to look sound will depend less on anything happening in Whitehall than on decisions taken in a White House answerable to none of the people who will feel the consequences in a hospital waiting room.