UK business growth weakest since September as Iran war drives up costs, survey shows

The UK composite PMI fell to 51.0 in March from 53.7 in February, signalling the slowest growth in six months while manufacturers’ input prices surged to 70.2 from 56.0 — the largest month-on-month jump since 1992. Oil prices rose over 2% amid the Middle East conflict, and businesses reported the fastest output price increases since April 2025, intensifying inflationary pressures. Employment declined for the 18th consecutive month and the BoE, which left rates on hold last week, warned inflation could rise toward 3.5% mid-year, heightening the case for further tightening. Supply-chain, transport and energy cost shocks tied to the geopolitical conflict pose downside growth and upside inflation risks for UK markets.

Analysis

An exogenous energy-cost shock to the UK economy will disproportionately shorten the runway for capital-intensive and export-exposed manufacturers: inventories will be drawn down and capex plans deferred, producing a two-to-six month drag on reported activity even if final demand holds. That mechanical hit amplifies margin dispersion — firms with real-time pricing models and hedged fuel exposures (large staples, integrated energy) will protect EBITDA, while small-to-mid cap suppliers and OEMs with fixed-contract backlogs will see compressed margins and working-capital stress.

Monetary policy is now being asked to thread a narrowing needle: leaning against inflation risks will push short-term yields higher and further squeeze consumption, but inaction risks de-anchored inflation expectations and steeper medium-term real rates. The most likely path over 3-9 months is higher front-end yields, a marginally weaker sterling, and greater volatility in break-even inflation — an environment that favors short-duration, inflation-protected strategies and FX volatility plays.

The market’s reflex has been to price commodity risk into energy and select cyclicals, but a second-order winner is UK exporters to non-sterling markets: a softer pound paired with sustained input inflation creates a window where export volumes can be supported while domestic competitors retrench. Conversely, supply-chain stress will concentrate counterparty risk in tier-2/3 suppliers and freight/logistics providers; credit spreads there can widen quickly if input shocks persist beyond one quarter.

Key Decisions for Investors

• 1) Brent call spread (ICE Brent futures): buy 1–3 month 0x3 call spread (long nearer-term ATM call, sell higher strike call) — rationale: asymmetric oil upside with limited premium. Timeframe 1–3 months; reward: 2–4x premium if Brent sustains a $5–$15 upward move; risk: full premium if conflict cools rapidly.
• 2) Buy GBP put options vs USD (3–6 month expiry, strike ~3–4% OTM) — rationale: BoE hesitancy vs Fed differential and energy shock favor GBP downside. Timeframe 1–6 months; reward: 3–6x option premium on a sharp sterling move; risk: premium loss if risk sentiment normalizes or BoE pivots to clearer tightening.
• 3) Pair trade: long Unilever (ULVR.L) and long Shell (SHEL.L) vs short CRH (CRH.L) — overweight defensive pricing-power and integrated energy cashflow vs cyclical building-materials exposure. Timeframe 3–12 months; expected skew: 300–500bps relative margin outperformance for longs vs short in a persistent input-cost scenario; risk: weaker-than-expected input-cost pass-through or construction acceleration could invert outcome.
• 4) Tactical credit: buy protection or underweight tier-2 UK industrial credits and logistics names (select high-BBB/low-BB issuers) — rationale: concentrated working-capital stress and widening spreads if supplier margin compression persists. Timeframe 3–9 months; reward: spread tightening >100–300bps in resolution scenarios; risk: sovereign/monetary stabilization causing base spread compression.