Gilts: Yields Surge Then Retreat as BoE Holds

The arc of UK gilt yields in 2026 tells a story of a market caught between two opposing forces. From a January low of 4.45% — a reading that seemed to confirm the BoE's easing trajectory — yields climbed through February and then accelerated sharply in mid-March as the Iran conflict escalated, briefly clearing 5% before retreating to approximately 4.80% in early April as de-escalation diplomacy gathered pace.

The trajectory is significant. The September 2025 peak was 4.69%. Yields have now moved well above that level at their recent highs, representing a regime shift rather than a temporary dip. The move from 4.45% to 5%+ in roughly ten weeks is unusually sharp for the gilt market outside of periods of acute stress.

US 10-year Treasury yields have risen too, but more modestly — from around 4.02% in late February to 4.33% now. The UK-US yield spread has widened to approximately 47 basis points from the 40–45bp range seen earlier in the year, reflecting the UK's greater sensitivity to energy price shocks through the Iran corridor and the stickier domestic inflation picture.

The Bank of England's March 2026 decision was stark in its unanimity. All nine members of the Monetary Policy Committee voted to hold Bank Rate at 3.75%, a signal that the committee is not prepared to ease into an inflation shock driven by geopolitical energy price pressure.

UK CPI stood at 3.0% in February and is widely expected to rise further as energy costs feed through. Services inflation — the BoE's preferred gauge of domestic price pressure — has remained persistently above 4%. Against that backdrop, the case for further cuts evaporated between January, when markets priced four reductions, and mid-March, when those same markets briefly priced potential hikes.

The current position is significantly less dovish than where the market stood three months ago. Fewer than two cuts are now priced for the remainder of 2026 — a dramatic compression from the four that were expected in mid-March. The BoE is now navigating a genuinely difficult dual mandate challenge: inflation running above target on one side, and softening growth alongside fiscal pressure on the other.

The Federal Reserve, for its part, has held the federal funds rate at 3.64% through this period — unchanged since late 2025. The BoE's decision to hold while the Fed also holds has kept the sterling-dollar dynamic broadly stable, but any divergence — a US cut while the UK holds, or vice versa — could introduce currency volatility that complicates the inflation outlook further.

The UK government's borrowing costs have risen materially with gilt yields. The Debt Management Office's issuance programme — running above £230 billion annually in gross terms — must now be funded at yields 35 basis points higher than where they stood in January. Every 10 basis point rise in gilt yields adds approximately £1.8 billion to annual debt service costs over time as maturing debt rolls into new issuance at higher rates.

The Iran conflict has added an additional dimension to the fiscal picture. Defence spending commitments — already under pressure from NATO allocation targets — have been revised upward in response to the conflict. This adds to the structural borrowing requirement at exactly the moment when debt servicing costs are rising.

Chancellor Rachel Reeves's fiscal rules target a falling debt-to-GDP ratio within five years. The combination of higher yields and increased defence spending makes that target harder to hit without additional tightening, yet tightening further risks a growth shock. The Office for Budget Responsibility's assumptions about nominal GDP growth — which determines how quickly the debt ratio falls — look optimistic against a backdrop of elevated energy prices and weakening consumer confidence.

For gilt investors, supply pressure remains a structural headwind. High issuance requires continuous demand at competitive yields. The Iran conflict has, paradoxically, both pushed yields higher (inflation fears) and attracted some safe-haven flows into gilts (risk-off demand). The net effect has been a yield spike followed by a partial pullback — not a clean directional move in either direction.

At 4.80%, long-dated UK gilt yields offer the best sustained income since the 2008 financial crisis. That is a genuine attraction for income investors, pension funds, and liability-matching buyers. However, the investment thesis has changed from what it was in January.

Three months ago, gilts at 4.45% were a rate-cut play: buy now, collect income, benefit from capital gains as the BoE cuts. Today, with fewer than two cuts priced and inflation potentially rising further, the capital gains element of the thesis is much less certain. What remains is the income: 4.80% on a UK government-backed instrument with CGT exemption.

Short-duration gilts (1–5 years) continue to offer the best risk-adjusted profile. They are most sensitive to eventual BoE rate reductions — when they come — and carry less duration risk if the Iran conflict re-escalates and pushes yields back toward 5%. The thesis has shifted from "rate cut play" to "inflation-protected income" — a subtly different but still compelling case.

Longer-dated gilts (15–30 years) offer higher yields but meaningful price sensitivity. A 25 basis point move in yields translates to roughly 4–5% price movement on a 20-year gilt. Given the current uncertainty, investors with shorter time horizons or lower risk tolerance should be cautious about duration extension.

For portfolio construction, gilts retain their role as a hedge against equity market volatility and recession risk. The negative correlation with equities has partially reasserted itself as the Iran conflict creates genuine growth uncertainty. A 10–20% allocation to short-to-medium dated gilts provides both income above 4.5% and downside protection in a risk-off scenario.