4.35% Looks Expensive Until the Strait of Hormuz Closes. Fix Your Mortgage Before the MPC Loses Its Nerve.

The spread between the Bank Rate and new mortgage rates has collapsed to 60 basis points. In Q1 2026, 94.7% of gross mortgage advances were priced at less than 2% above Bank Rate — the lowest share since early 2023.

Lenders have been tightening that spread for three consecutive months. April: 4.08%. May: 4.22%. June: 4.35%. That's a 27-basis-point rise in a quarter where the MPC did nothing.

What's driving this? Swap rates. The 2-year SONIA swap — the benchmark lenders use to price fixed-rate mortgages — tracks gilt yields more than it tracks the Bank Rate. And UK 10-year gilt yields at 4.80% are pricing in a world where rates stay higher for longer.

The tracker discount is being arbitraged away in real time. A typical 2-year tracker at base rate + 0.40% gets you 4.15%. A competitive 2-year fix sits at 4.25% to 4.50%. The gap is 10 to 35 basis points. On a £200,000 mortgage, that's £17 to £58 a month. You're risking your entire monthly budget on that difference.

This narrowing spread mirrors what happened in late 2022 — lenders price risk before the MPC acts. Use our mortgage calculator to see exactly what each option costs you.

The Bank of England's last rate move was 18 December 2025 — a quarter-point cut from 4.00% to 3.75%. That was 229 days ago. Since then: nothing.

Seven months of unchanged rates. The MPC has watched mortgage rates drift up, house price growth flatline at 0.1%, and the US Federal Reserve hold at 3.63%. They've watched petrol prices spike on Iran tensions. They've watched — and they've waited.

This is not a committee straining at the leash to cut. This is a committee that remembers 2022. It remembers cutting too late and hiking too fast. It knows the UK economy faces recession risk if the Strait of Hormuz remains closed — but it also knows a supply-side oil shock is the one scenario where cutting rates would be catastrophic. Lower rates when petrol is spiralling? That's a sterling crisis waiting to happen.

The MPC's next move could be a cut. But it could also be nothing for another six months. Or it could be an emergency hike if Iran escalates. A tracker mortgage exposes you to all three. A fix eliminates two of them. As we wrote in July, the BoE holding pattern is now the longest since 2021. The ONS house price data confirms buyers have gone into wait-and-see mode — and the MPC is doing the same.

Let's put numbers on it. A £200,000 mortgage over 25 years:

• 2-year tracker at base rate + 0.40% = 4.15%: £1,070/month
• 2-year fix at 4.35%: £1,094/month
• Difference: £24/month, £576 over two years

If the MPC cuts once — one quarter-point — your tracker drops to 3.90% and you're paying £1,042/month. You save £52/month vs the fix and feel clever.

If the MPC holds for two years: you saved £576. Fine.

If the MPC hikes — even once — to 4.00%, your tracker hits 4.40%, you're paying £1,100/month. You're now worse off than the fix, but only by £6/month. Manageable.

But that's not the scenario that breaks households. The scenario that breaks households is 2022-redux: Iran closes the Strait, oil hits $150, CPI spikes, the MPC panics, and rates go to 5.00%. Your tracker hits 5.40%. That's £1,216/month — £122/month more than your fix, £2,928 over two years.

The upside of a tracker is £52/month. The downside is £122/month. The bet is asymmetric — in the wrong direction.

The UK 10-year gilt yield has averaged 4.67% over the past 12 months, with a June 2026 reading of 4.80%. It hasn't dipped below 4.43% since February.

Gilt yields are the market's collective judgment on future Bank Rate, plus an inflation premium, plus a term premium. When gilt yields are 105 basis points above the Bank Rate and rising, the market is telling you it doesn't believe 3.75% is sustainable — but in which direction?

If the market expected aggressive cuts, long-dated yields would be falling. They're not. Gilt yields in June 2026 (4.80%) are higher than they were in February 2026 (4.43%). The market is pricing in inflation persistence, geopolitical risk, or both.

Fixed-rate mortgages are priced off swap rates, which derive from gilt yields. When gilt yields rise, fixed rates follow. That's exactly what's been happening since March. The window to fix at sub-4.25% is closing — and if the August MPC statement contains any hawkish language about Iran, it could close fast.

This is the same dynamic we identified when analysing the 4.66% fixed-rate market in July: the time to lock in is when the narrative still has room to deteriorate. The BoE's effective rates data shows the gap between new business rates and outstanding rates widening — that gap is your window.

Choosing a tracker is making three bets simultaneously:

Bet 1: The MPC cuts rates in the next two years. Reasonable, but not certain. The latest BoE data shows mortgage arrears at their lowest since Q3 2023 and new commitments up 14.2% year-on-year — the housing market isn't screaming for a bailout.

Bet 2: Those cuts are passed through to your tracker rate in full and immediately. Also reasonable — tracker mortgages contractually follow the base rate.

Bet 3: Nothing happens that causes rates to go up. This is the bet that should make you pause. The Guardian reports UK petrol prices at Iran-war highs. EY warns of recession if the Strait of Hormuz stays closed. Oil supply shocks have ended every rate-cutting cycle in modern British history.

A tracker only wins if Bets 1, 2, and 3 all land. A fix wins if any one of them fails. That's not a 50/50 proposition — it's stacking the odds against you.

At £24/month extra for a fix over a tracker, the insurance premium is trivial. Most households spend more on Netflix, Spotify, and a takeaway.

What does that £24 buy you? The ability to budget precisely for two or five years. No late-night anxiety about MPC minutes. No panicked remortgage search if swap rates spike. No exposure to an Iranian escalation that Treasury analysts are already modelling as a UK recession trigger.

For first-time buyers, this matters even more. The BBC reports it may be easier to get a first mortgage than you think — but that means more stretched borrowers entering the market. A stretched borrower cannot absorb a rate shock. A stretched borrower needs a fix.

For the over-55s tapping equity — borrowing £113,779 on average — a tracker is reckless. Retirement income doesn't flex with the Bank Rate. Your mortgage payment shouldn't either. That group has already seen the value of certainty eroded by stamp duty costs — adding rate risk on top is compounding the mistake.

And if you're weighing fixing against the alternative of simply overpaying a variable-rate mortgage, the math converges on the same conclusion: certainty is underpriced. For a full breakdown of fixed-rate options across the market, see our mortgages hub.