Gilt yields back at crisis-era highs

The yield on the benchmark 10-year gilt crossed the five per cent threshold on Tuesday for only the third time since the Iran war began on 28 February, according to MarketWatch data. The move marks the highest level since the aftermath of the global financial crisis and eclipses the brief spike that accompanied the October 2022 mini-Budget under Liz Truss.

The path here has been volatile. Gilt yields drifted lower through the first quarter of 2026, buoyed by a run of better-than-expected public borrowing figures and record tax receipts. Markets had begun pricing in a more benign inflation outlook and a resumption of Bank of England rate cuts. That relief rally unwound sharply once the war disrupted oil flows through the Strait of Hormuz and Brent crude climbed from pre-conflict levels of roughly $75 to $80 a barrel to more than $111 on Tuesday, as reported by City AM, after ceasefire talks between the US and Iran collapsed.

At the shorter end of the curve, the damage has been even more pronounced. The two-year gilt yield, which tracks the expected interest rate path most closely, has risen by more than a full percentage point since the start of March, according to City AM. Traders have been forced to pare back earlier bets on Bank of England cuts aggressively.

Why the UK is paying more than its peers

The sell-off has not been confined to gilts, but Britain is bearing a disproportionate share of the pain. The spread between the 10-year gilt yield and the equivalent US Treasury rate has widened to 70 basis points, a level reached only once before, in late 2025, according to MarketWatch data.

The core reason is energy exposure. The UK is a net importer of oil and gas, covering roughly 35 to 40 per cent of its primary energy needs from overseas, according to Department for Energy Security and Net Zero statistics. That compares unfavourably with the United States, which is broadly energy self-sufficient, and sits closer to the import dependency of Germany and France, both of which have more diversified supply arrangements and larger strategic reserves. A sustained Brent price above $110 translates into a materially wider current-account deficit for the UK and feeds directly into imported inflation.

"Over the past decade, the UK economy has suffered a succession of policy mistakes and resulting rates of inflation which have consistently exceeded the prevailing trends across other major economies. Unsurprisingly, it no longer takes much to spook UK government debt markets."

That assessment, from Kallum Pickering, chief economist at Peel Hunt, captures a broader sell-side consensus. The argument is that a sequence of shocks, from Brexit through the Truss mini-Budget to the post-Ukraine inflation overshoot, has embedded a persistent risk premium into gilts. The Iran war has simply widened it further.

Kathleen Brooks, research director at XTB, noted that yields were "likely to creep higher as we lead up to the key central bank meetings this week, and as we wait to hear what happens next in the Strait of Hormuz," as reported by City AM.

What five per cent means for business borrowing

For operators running mid-market businesses, the gilt yield is not an abstraction. It is the reference rate that underpins a wide range of real-economy borrowing costs.

Commercial lending and refinancing

UK bank lending to SMEs is typically priced as a margin over the relevant swap rate, which itself tracks gilt yields closely. A 10-year gilt yield at five per cent implies swap rates in a similar range, meaning a firm refinancing a five-year term loan today could face an all-in cost of seven to eight per cent or higher, depending on credit quality and sector. That compares with rates of roughly five to six per cent available as recently as early 2025.

For businesses with floating-rate facilities linked to SONIA, the short end of the curve matters more. The jump in two-year gilt yields signals that markets expect the Bank Rate to remain elevated for longer, keeping SONIA-linked borrowing costs high.

Commercial property

Commercial mortgage rates follow gilt yields with a lag. A sustained five per cent 10-year yield compresses the margin between rental yields and financing costs, making new investment in commercial property harder to justify on a cash-flow basis. Firms occupying leased premises may find landlords less willing to offer favourable terms at renewal, as property owners face their own refinancing pressures.

Public-sector contracts

Any contract indexed to gilt yields, or to the Retail Prices Index that tends to move in sympathy with inflation expectations embedded in gilts, becomes more expensive for the contracting authority and, by extension, more uncertain for the supplier. Firms reliant on government or NHS procurement should expect tighter budget scrutiny.

Hiring and investment

The cost of capital is a direct input into investment appraisal. A higher discount rate raises the hurdle for new projects, expansion plans, and headcount growth. For scale-ups seeking equity or venture debt, the effect is indirect but real: investors recalibrate return expectations upward when risk-free rates rise, making fundraising harder.

Outlook: rate cuts, fiscal headroom, and the oil price

The Bank of England's dilemma

The Monetary Policy Committee held Bank Rate at 4.5 per cent at its last meeting. Before the Iran war, swap markets had been pricing in two to three quarter-point cuts by the end of 2026. That expectation has been sharply revised. Market-implied rates now suggest the Bank may deliver only one cut this year, and some traders are not ruling out a hold through the remainder of 2026.

The next MPC meeting is closely watched. Policymakers face a tension between weakening growth data and an energy-driven inflation impulse that could push CPI back above target. Cutting rates into a supply-side shock risks embedding higher inflation expectations; holding rates risks deepening a slowdown.

Fiscal headroom under pressure

Higher gilt yields feed directly into the government's debt-servicing bill. The Office for Budget Responsibility's latest published estimates gave Chancellor Rachel Reeves a slim margin of fiscal headroom against her own borrowing rules. Rising yields erode that margin pound for pound: each basis-point increase in average gilt yields adds hundreds of millions to annual interest costs across the government's debt stock.

Reeves's Spring Statement commitments, including pledges on public investment and departmental spending, were predicated on borrowing costs that now look optimistic. The Chancellor may face difficult choices if yields remain at or above five per cent into the autumn, when the next fiscal event is expected.

Oil as the swing factor

The trajectory of Brent crude remains the single largest variable. A resolution or de-escalation in the Strait of Hormuz could bring oil back toward the $80 to $90 range, relieving pressure on inflation expectations and allowing gilt yields to retrace. A further escalation, or a prolonged disruption to tanker flows, could push crude higher still and entrench the current yield environment.

For UK businesses, the practical implication is straightforward. Borrowing costs are high and may stay high. Firms with near-term refinancing needs, capital expenditure plans, or exposure to energy input costs face a more hostile environment than at any point since the financial crisis. Planning for a sustained period of expensive capital is, for now, the prudent course.