Can a Interest only Mortgage Balance increase?

nxf

I have a 25 year Barclays Buy-to-let Interest only Mortgage which started on 2013.
I have never missed a payment.
For 12 years the balance has remained the same. In February 2025 they have started using a new calculation which means my balance is slowly creeping upwards. Are they allowed to do this mid term?
Its hard to calculate the exact amount because the spreadsheet they sent to me has a few errors which means it is between £100 & £200 a year.
I have complained, they refuse to listen so will send me a final response letter I can take to the ombudsman

El_Torro

I can understand it increasing a few pounds a year due to rounding. Between £100 and £200 a year sounds a lot though. This doesn't include charges, for example when you go to a new term? 

kingstreet

I'd expect it to increase from the beginning to the end of a month then fall back once the payment has been received.

nxf

Thank you. There are no charges added. The reason they gave for the higher balance is they transferred my account to a new system.

They also changed the instalment due date. It used to be the same day as the direct debit (3rd). The d/d day is still the same but the Instalment date is now the 16th. This means when you get a new rate switch for example, they calculate using a higher balance.

This appears appears wrong/crafty/dishonest/illegal? to me as I expected the balance to be the same at the end of the mortgage as it was at the start because it had done so for 12 years and its interest only I am paying.

Typhoon2000

Did you do a rate switch in early 2025 or there abouts? If so what  effective date for the switch did you choose? Of your mortgage payment went up due to a rise in rates, did your payment go up the same month at the rate switch or the next month? 

Caz3121

nxf said:

They also changed the instalment due date. It used to be the same day as the direct debit (3rd). The d/d day is still the same but the Instalment date is now the 16th. This means when you get a new rate switch for example, they calculate using a higher balance.

as interest is accrued daily could it be this change that has affected the balance as an additional 13 days interest added