A BBC Business video doing the rounds this week asked a question that used to have a fairly simple answer: if you've got some spare money, should you save it or use it to pay down your mortgage? For years the advice barely changed. Now it does, because the backdrop has shifted under everyone's feet.
The Bank of England held its base rate at 3.75% on 17 September, but the vote was far from unanimous. The Bank of England held interest rates at 3.75% on 17 September, with six members voting to hold and three members voting to increase rates to 4%. That's a genuinely split committee, and it tells you something about how finely balanced the argument has become. The most recent Office for National Statistics figures released in September showed that CPI inflation increased to 3.1% in August, and the Bank's own language hasn't been reassuring. The Bank warned that interest rates may need to rise if the conflict in the Middle East continues and higher energy prices lead to more persistent inflation, with Governor Andrew Bailey saying the longer the conflict continues, the more likely it is that the Bank will need to raise rates to bring inflation back to its 2% target.
Fixed rates are moving even without a base rate change
Here's the twist that makes this more than an academic argument. Homeowners might assume that a held base rate means calm on the mortgage front. It doesn't. All of the UK's big six mortgage lenders have increased fixed rates this month, and all have now repriced for a second time since the start of September, with some lenders increasing by as much as 0.43 percentage points. That's because fixed deals aren't priced off the base rate at all, they're priced off swap rates, the wholesale cost lenders pay to lock in borrowing for two or five years. Those have been climbing steadily as markets brace for a possible rise rather than a cut. One mortgage adviser summed up the mismatch bluntly: though this is a welcome relief for those borrowers on a tracker rate mortgage, the fixed rate market tells a bit of a different story.
Put plainly, tracker borrowers get a breather this month, but anyone coming up to remortgage on a fixed deal is walking into a slightly worse market than they might expect, base rate hold or not.
The rule of thumb everyone's asking about
This is the context for the advice at the centre of the BBC piece, drawn from personal finance broadcaster Martin Lewis. His framework is simple and hasn't really changed, even as the numbers around it have. UK interest rates look like they're going to rise this year, and it is no surprise that lots of people are asking whether to use spare cash to save or to overpay their mortgage. His answer comes down to comparing two numbers. If your mortgage rate is higher than the after-tax rate you can earn on savings, you're generally better off overpaying the mortgage. If your savings rate is higher than you're paying on your mortgage, you're generally better to save.
He adds two practical caveats that matter more than ever right now. Always make sure there aren't any penalties for overpaying your mortgage, since most people can overpay 10% a year without a problem. And don't strip your safety net to do it: always keep an emergency fund, three to six months' worth of bills, aside before you overpay the mortgage, because an overpayment won't stop arrears building up if something goes wrong later.
There's a third point that's easy to overlook and arguably the most relevant one for anyone in Kent sitting on a chunky mortgage balance. If you're coming up to remortgaging and your loan-to-value is high, borrowing less at that point could unlock a noticeably better deal, so it might be worth keeping savings accessible to reduce the mortgage right at the moment you remortgage rather than drip-feeding overpayments throughout the term.
Why this bites harder here than elsewhere
The mortgages we're talking about in this part of the county aren't small. Properties across the higher-value pockets of Kent we track average £877,842, which means the pounds and pence behind Lewis's rule of thumb are considerably larger than they'd be on a typical first-time buyer loan. A quarter of a percentage point on a mortgage that size moves real money, month to month. It's worth remembering that this sits well above the county-wide picture too. Earlier this year, average Kent property prices increased 1.6% in the 12 months to May 2026, taking the typical home to £345,918. The gap between that figure and the higher end of the market we cover shows just how varied Kent's mortgage exposure is from one postcode to the next, and why blanket advice needs local translation.
For someone with a large fixed rate maturing in the next year, the loan-to-value point isn't theoretical. Chip away at the balance now, and a remortgage in twelve months could land in a meaningfully cheaper pricing tier. Sit on cash in an easy-access account instead, and you're betting that savings rates stay competitive enough to beat what you're paying on the mortgage after tax. Both can be right answers, depending on the household, which is exactly why Lewis frames it as a comparison rather than a rule.
The waiting game into November
The Monetary Policy Committee's next scheduled decision falls on 5 November, alongside a fresh Monetary Policy Report. Nobody knows yet which way that vote will go, and anyone telling you otherwise is guessing. What we do know is that markets have been pricing in the possibility of increases rather than cuts since the autumn began, and that fixed rate mortgages have already started moving in anticipation, regardless of what the base rate itself eventually does.
That's the uncomfortable reality for anyone weighing up savings versus overpayments right now. The old certainties, rates only go one way, fixed deals track the base rate, cash in an easy-access account will always lose to a mortgage overpayment, don't hold in quite the same way they did a year ago. Households across Kent with larger balances and larger stakes would do well to run the actual numbers on their own mortgage rather than lean on last year's assumptions. The gap between what the Bank does next month and what lenders have already done this month is where the real decision lives.