The average UK two-year fixed-rate mortgage has climbed from 4.83% on 1 March 2026 to 5.78% on 1 May, according to data published by Moneyfacts. Five-year fixes moved from 4.95% to 5.68% over the same eight-week period. The reversal — driven entirely by the Iran war energy shock and its impact on UK inflation expectations — has left approximately 1.6 million UK households due to remortgage in 2026 facing materially higher monthly payments than they had budgeted for.
The arithmetic of the remortgage cliff
For borrowers exiting sub-3% fixes taken before the September 2022 Truss mini-budget, the implied jump is severe. On a typical £200,000 capital-and-interest loan over 25 years, moving from a 2.5% fix to a 5.78% fix increases monthly repayments from approximately £897 to £1,259 — a rise of £362 per month, or £4,344 annually. Larger loans amplify the effect: a £350,000 mortgage sees the monthly bill climb by approximately £634. This is happening alongside the unfreezing of National Insurance thresholds and the tightening of personal allowances since the Autumn Statement, compounding the squeeze on household disposable income.
Why rates moved so fast
The reversal traces directly to the December 2025 Bank of England statement, which had cut Bank Rate to 3.75% in a 5-4 vote and signalled “a gradual downward path” with markets pricing a terminal rate of 3.25% by year-end. The Iran war that erupted in late February 2026 wholly upended that trajectory. UK CPI rose to 3.3% in March from 3% in February, with motor fuels the dominant contributor. NIESR warned that if the conflict drags on, inflation could reach 5-6% by end-2026. Markets repriced the Bank Rate path: the December 2026 implied rate has moved from 3.25% to 3.75%, with a non-trivial probability of a hike to 4.00% if Brent breaches $130 per barrel sustainably.
Who’s most exposed
The most exposed segment is the cohort of borrowers who fixed in 2020 and 2021, when sub-2% five-year deals were widely available. Those expiring in mid-to-late 2026 face the largest payment jumps. By contrast, borrowers who fixed in 2022 and 2023 at higher rates may, perversely, see modest reductions if the Iran war eventually de-escalates and BoE returns to its easing path. Mortgage brokers report that tracker products have become more attractive at the margin, on the bet that rates fall later in 2026 — but advisers caution against tracking strategies for households without significant cash buffers given the asymmetric risk if Brent moves above $130.
Lenders respond: criteria tighten, products shift
Major lenders including Halifax, Nationwide, Barclays, NatWest and Santander have repriced repeatedly through April. Some have widened their loan-to-income caps for first-time buyers as a competitive response, but most have tightened affordability stress tests, requiring borrowers to demonstrate they can service payments at higher hypothetical rates. Buy-to-let mortgage rates have moved similarly, with the additional pressure of recent income-tax changes that made BTL less attractive to amateur landlords. Halifax data shows monthly mortgage costs as a share of income are still at their lowest level since 2022 for first-time buyers — but the trajectory has reversed sharply since the start of the year.
The savings counterweight: ISA and fixed-deposit returns hold up
The flip side for cash holders is more positive. Best one-year fixed-rate cash ISAs pay 4.65% to 4.85% AER; easy-access savings accounts from challenger banks remain at 4.10% to 4.50%. With the £20,000 ISA allowance reset on 6 April 2026, advisers recommend savers fix at least a portion of their cash for 12-24 months in case the BoE is eventually forced to cut should energy prices retreat. NS&I Premium Bonds remain at a 4.40% prize-rate — broadly competitive given the tax-free nature of returns and the 100% government guarantee.
What to watch in the next 60 days
Three datapoints will determine whether mortgage rates fall back or push higher: (1) the April CPI release on 21 May; (2) the BoE Monetary Policy Committee meeting on 11 June; (3) any de-escalation or escalation around the Strait of Hormuz. President Donald Trump has publicly stated restrictions may remain “for months to come” — a duration that would lock in current mortgage rate levels. Borrowers facing remortgage decisions in Q2 and Q3 face a genuinely binary outcome and may wish to take professional advice before locking in or rolling onto SVR.
