What happened
Moneyfacts data published on 2 September put the average two year fixed mortgage rate at 5.59 percent and the average five year fix at 5.63 percent, reversing part of the decline seen over the summer. Rates eased through June and July on expectations of further Bank of England cuts, then turned back upwards through late August.
The Bank of England base rate itself has not changed. The Monetary Policy Committee held it at 3.75 percent on 30 July, with six members voting for no change and three voting to raise it by 0.25 percentage points. Three votes for a rise is unusually hawkish and told markets that the next move might be up rather than down. The next decision lands on 17 September.
What has actually moved is swap rates. These are the rates at which banks exchange a variable interest payment for a fixed one over a set period, and they are how a lender converts uncertain future funding costs into a fixed price it can offer you. Swap rates track expectations of where the base rate will be over the next two or five years, not where it is today.
Those expectations have shifted. With UK inflation at 2.9 percent in July and forecast to peak near 3.6 percent this month, markets have pushed back the timing of further cuts. Best buy deals remain far below the averages, with the sharpest five year fixes around 4.38 percent for borrowers with large deposits, but the gap between the best rate and the average rate has widened.
Why it matters
Roughly 1.6 million UK fixed rate deals come to an end each year. Many of those borrowers locked in when rates were far lower, so their remortgage is not a small adjustment but a step change in monthly cost that arrives all at once.
The numbers are large. On a 200,000 pound repayment mortgage over 25 years, the difference between a 4.5 percent rate and a 5.6 percent rate is roughly 125 pounds a month, or about 1,500 pounds a year. That is money removed from household budgets already absorbing higher energy bills from October.
It also matters for the housing market. Mortgage pricing is the main determinant of what buyers can borrow, and therefore of what they can offer. When fixed rates drift up, affordability calculations tighten, offers come down and transaction volumes slow. That feeds through to estate agents, conveyancers, removals firms, builders and everyone who sells sofas and kitchens.
Perhaps most importantly, this episode shows that the base rate is not the whole story. Households often assume that if the Bank of England holds or cuts, their mortgage will follow. For anyone on a fixed deal, the number that matters is the swap rate, and swap rates can rise while the base rate sits still.
Explained simply
The base rate is todays weather. Swap rates are the forecast for the next five years, and a fixed mortgage is priced off the forecast, not off what is happening outside the window right now.
When a bank offers you a five year fixed mortgage, it is making a promise. It guarantees your payment for five years even though its own cost of funding that loan will move up and down over that period. To keep that promise safely, the bank has to lock in its own costs first.
It does that in the swap market. The bank agrees to pay a fixed rate to another institution for five years in exchange for receiving a floating rate. That trade neutralises its risk. Whatever happens to the base rate, the bank knows exactly what its funding costs, so it can safely offer you a fixed price.
The rate it has to pay in that swap is set by what the whole market collectively expects the base rate to average over those five years. If traders think inflation will stay stubborn and the Bank of England will cut slowly or not at all, the swap rate rises immediately, long before the Bank does anything.
The lender then adds a margin on top to cover administration, capital requirements, expected defaults and profit. That is your mortgage rate. This is why fixed mortgage pricing can move sharply in a week when no central bank has met at all.
What it means for you
If your fix expires within the next six months, act now. Most UK lenders let you reserve a rate three to six months ahead of completion, and virtually all allow you to switch to a cheaper deal for free if rates fall before you complete. That is a free option in your favour, so taking it costs you nothing but protects you if swap rates keep rising.
Compare the two year and five year decision honestly. A five year fix at around 5.63 percent buys certainty through a period in which nobody can forecast energy prices. A two year fix at 5.59 percent is a bet that rates will be meaningfully lower in 2028. There is no universally correct answer, only the question of how much a bad surprise would hurt you.
Check your loan to value band before assuming you face average pricing. Lenders price in tiers, typically at 60, 75, 85 and 90 percent. If house price growth or capital repayments have pushed you just over a threshold, a small overpayment to cross into the next band can cut your rate by a quarter of a percentage point or more.
If you are on a standard variable rate after a fix ended, you are almost certainly paying far more than you need to. SVRs commonly sit above 7 percent, well above even the average fixed rate, and moving off one is usually the single largest saving available to a borrower.
The bigger picture
Britain is still working through the aftermath of the ultra cheap borrowing era. Deals taken out between 2020 and 2022 at rates near 1.5 percent are still rolling off, and every one of them repriced into a market where the equivalent product costs three or four times as much.
The 17 September decision will be scrutinised less for the rate itself, which most economists expect to be held at 3.75 percent, than for the vote split. If the hawkish minority grows from three, swap rates will rise further and fixed mortgage pricing will follow within days.
The variable that decides everything is energy. If Middle East disruption eases and gas prices fall, inflation drops back towards target, rate cut expectations return and fixed mortgage rates fall with them. If it does not, borrowers should plan for these levels to persist into 2027.
