TO: Whoever is still long UK duration
FROM: The Gilt Market
DATE: March 26, 2026
RE: We need to talk about what I've become
I'll keep this brief, because brevity is the one luxury I no longer afford anyone.
The 30-year yield closed at 5.45% on Wednesday. That is not a number. It is a message. The 10-year touched 5.1% on Monday — the highest since July 2008, a month before Lehman filed for bankruptcy — before retreating to 4.85% as the Trump-Iran ceasefire rumour briefly seduced the risk-off crowd. The 2-year is sitting at 4.38%, up 27 basis points in a single session last Thursday after the Bank of England held unanimously at 3.75% and two MPC members made noises about hiking.
Let me explain why this matters more than the oil price does.
Rachel Reeves stood before the Commons on March 3 and delivered her Spring Forecast with the quiet confidence of someone who had made peace with modest ambitions. The OBR had already written her the script: borrowing down, debt stabilising, inflation at 2.3% for 2026, the fiscal rules intact, growth at 1.1% — lower than the November forecast but nothing catastrophic. The Chancellor declared that "inflation is down, borrowing is down, living standards are up and the economy is growing." She probably believed it.
The OBR had a footnote for that. The Spring Forecast was finalised before conflict escalated in the Middle East. That footnote has since eaten the entire document.
Brent was trading around $84 when Reeves gave her speech. It hit $119 before pulling back to $102. The OBR's central forecast had Brent averaging $90 for the year before gliding back to $60. S&P Global's alternative scenario — persistent disruptions, higher-for-longer energy — has Brent peaking at $200 a barrel in Q2 and remaining above $100 at year-end, which would tip the UK, Japan, and Germany into recession. That scenario is no longer a tail risk. It is the conference room nobody wants to book.
The OBR had projected the UK would spend £109.7 billion servicing its debt in 2025-26 and £109.4 billion in 2026-27. Given that government debt is already at 96% of GDP and the yield on 10-year gilts now exceeds that of every other G7 nation, these numbers are already stale. Every 25 basis points the market reprices upward translates into billions more in refinancing costs across the issuance calendar. The DMO cannot finesse this. The Chancellor cannot wish it away. The arithmetic is what the arithmetic is.
What is happening to gilts right now is not chaos. It is recognition. The market is completing a process of understanding that the UK's fiscal position is structurally exposed in ways that peer economies are not.
Start with the basics. Britain has no meaningful domestic energy production relative to its consumption. It is an island, deeply integrated into European energy pricing, with a retail energy market that transmits wholesale shocks directly to households via the price cap mechanism. The Bank of England now expects March CPI at 3.5% year-on-year, up from a prior forecast of 3.1%, explicitly linked to higher fuel prices. Services CPI came in at 4.3% in February — not the 4.1% the BoE had modelled. Core unexpectedly ticked up to 3.2%. The Bank voted unanimously to hold. Prior to that meeting, markets had fully priced one hike this year with roughly a 50-50 chance of a second. After the statement, two hikes by year-end became the central case.
Now layer in what the British economy cannot absorb. Growth at 1.1% — and the OBR made that forecast before the war materially changed energy prices. Unemployment projected to peak at 5.3% this year, nearly half a point above November estimates, with close to a million young people not in education, employment, or training. Flash PMI for March came in at 49.5, the first contractionary reading in eight months. The economy is slowing into an inflation shock. The Bank of England is being asked to choose between the two things it cannot afford to get wrong simultaneously.
Compare what's happened to UK borrowing costs with peers since the conflict began. German 10-year bunds rose 42 basis points. US 10-year Treasuries rose 48 basis points. French OATs rose 64 basis points. UK gilt yields rose substantially more. Of comparable developed economies, only Australia has a higher 10-year yield.
There is no mystery here. The UK was already the highest-rate G7 central bank when this started. It had sticky services inflation, a weak productivity picture, a government dependent on rising receipts rather than spending discipline, and a political class in no position to deliver fresh austerity. The energy shock did not create these vulnerabilities. It illuminated them.
For a sense of proportion, consider the last time gilts traded at 5% with this kind of trajectory. Investors demanded a substantial premium to hold gilts for much of the mid-to-late 1970s, when UK inflation hit 26.9% in August 1975 and was never below 19% that year, driven by oil shocks earlier in the decade. The UK was ultimately forced to seek an IMF loan in 1976. One does not raise 1976 as prediction. One raises it as proof that this country has been here before and that the path from energy shock to sovereign credibility crisis is shorter than most people assume.
The 2022 mini-budget crisis — Kwarteng, 45 days, LDI margin calls — demonstrated that gilt markets can break in ways that force hand. That episode was triggered by a £45 billion unfunded tax cut. The current stress is being driven by a global energy shock that the British government did not cause and cannot control. But the distinction matters less to the market than the outcome: higher yields translate directly into higher borrowing costs, and Reeves has built her fiscal framework around stability and credibility. A framework built for calm seas does not automatically survive a force-nine gale.
The BoE's bind is real. The SONIA forward curve is now pricing at least two 25-basis-point hikes by year-end. The Bank will resist this. Not because it is wrong to resist — a cost-push shock in a slowing economy is not what rate hikes are designed to cure — but because the market will not let it sit still for free. Every month it holds, it risks further unanchoring of inflation expectations. Every month it hikes, it accelerates the slowdown it is trying not to cause. This is the stagflation trap, textbook edition, and the BoE is standing inside it.
The memo, then, is this.
The gilt market is not broken. It is doing exactly what markets do when the variables change: repricing. The people who should be uncomfortable are not the traders short duration. They are the policymakers who built a fiscal consolidation plan entirely dependent on energy prices cooperating, growth holding up, and unemployment staying politely below 5%.
Two of those three assumptions are already gone.
The 30-year is at 5.45%. The yield has risen 38 basis points over the past month. The OBR's Spring Forecast is already a historical document. And Rachel Reeves is going to need a budget — a real one, with real numbers — sometime before the autumn, whether the annual cycle calls for it or not.
