Remortgage delays could cost borrowers hundreds in extra interest

For the approximately 1.8 million homeowners whose fixed-rate deals are due to expire in 2026, securing a new mortgage offer is only half the battle. Paperwork delays that allow a remortgage to drift past its intended completion date can push borrowers onto their lender's standard variable rate (SVR) — and new analysis from conveyancing firm RG Law shows the financial cost of those hold-ups is far from trivial.

According to RG Law's calculations, a four-week delay costs a borrower with a £150,000 mortgage approximately £138 in additional interest. On a £250,000 balance that rises to £230, and on £350,000 to £322. The figures are based on the 1.20-percentage-point difference between Moneyfacts' October average SVR of 7.13% and its average two-year fixed rate of 5.93%.

The cost of waiting

The numbers hold firm across a range of timeframes. A two-week delay costs the same borrowers £69, £115, and £161 respectively — but if that slips to six weeks, the additional interest climbs to £207, £345 and £483.

Source: RG Law analysis using Moneyfacts October 2026 average rates. Calculations assume unchanged balance; exclude fees, capital repayments and early repayment charges.

Karen Marsh of RG Law said a mortgage offer reaching the client's desk is an important milestone, but it does not mean a case is ready to complete. "Completing on time can help homeowners avoid an unnecessary period on their lender's standard variable rate," she said. "Brokers and lenders put considerable work into securing the right mortgage for their clients. Our role is to support that work through to completion, keeping everyone informed and helping resolve outstanding requirements."

With the Intermediary Mortgage Lenders Association (IMLA) forecasting £110 billion of remortgage lending in 2027, the aggregate cost of administrative delay across the market is substantial.

Matt Hurren, director at Novum Mortgage Services Ltd, said those forecasts underline the importance of preparing early. "Securing a suitable mortgage deal is only part of the process," he said. "When switching lenders, the legal work must also be completed on time. Delays could leave borrowers on their existing lender's standard variable rate, adding interest costs that erode the benefit of switching."

What causes the hold-ups

Delays rarely originate from a single point of failure — and they aren’t often the fault of one party alone.

According to RG Law, outstanding identity documents, incomplete client forms and signed mortgage deeds returned late are among the most common causes — each capable of stalling an otherwise straightforward case. Homeowners unfamiliar with the remortgage process may not realise what is being asked of them, or how quickly they need to respond.

For leasehold properties, the process is more complex still. Repayment figures from the existing lender and information from freeholders or managing agents may also be required before a case can progress, and those third parties operate on their own timescales.

The common thread is preparation. Cases that run into difficulty are often those where the legal process was not started early enough, or where the borrower was not given clear guidance on what was needed and when.

What brokers and conveyancers can do

The message from both Marsh and Hurren is consistent: early coordination is the most reliable way to keep a remortgage on track. That means brokers flagging the legal process to clients as soon as a rate switch is being considered — not once the mortgage offer lands.

"Close coordination between borrowers, mortgage advisers and conveyancers helps identify potential obstacles early and keep completion on track," Hurren said. "Securing the right deal and completing the legal work on time go hand in hand."

Marsh agreed, noting that while conveyancers can only control so much, clear communication with clients makes a material difference. "We focus on what we can influence: progressing the legal work promptly, giving homeowners clear instructions and dealing with queries as they arise," she said.