Taking your mortgage with you.

The thing that catches people out

A port is not a transfer. You apply again. Your income is assessed again, your credit file is pulled again, and the decision is made against whatever the lender's rules say on the day you apply — which may be nothing like the rules you satisfied when you bought.

So the person who completed three years ago in good order, then had a rough patch — a default, a missed run of payments, a debt arrangement — can be told they cannot take their own mortgage to their own next house. They have never missed a payment on that mortgage. It counts for less than you would expect.

The sting is what follows. If the port is refused and you move anyway, you are redeeming the mortgage — and if you are inside a fixed period, the early repayment charge usually applies. You end up paying to leave a deal you were trying to keep.

Why the timing matters more than anything else

Most people ask about porting after their house is on the market, often after they have accepted an offer. By then a refusal is expensive: a chain is forming around a mortgage that may not travel.

Asked early, the same refusal is just information. There is usually more than one route — a different lender for the whole purchase, a change to the timing, sometimes waiting a few months for something to drop off the file. None of those are available once contracts are moving.

If there is anything on your credit file since you took the mortgage out, find out where you stand before the estate agent's board goes up.

Borrowing more at the same time

Moving to a more expensive house usually means porting the existing balance and borrowing the difference. That additional borrowing is assessed on its own and commonly sits on separate terms from the ported part, so you can end up with one mortgage made of two pieces that end at different times.

It also means there are two things that can be declined rather than one. A decline on the extra borrowing does not always kill the port itself — sometimes a smaller purchase still works. That is worth knowing before you conclude the whole plan is dead.

Things worth knowing before you commit to a move

• Permission to port is not permission to borrow more. They are separate decisions.
• The property has to suit the lender too. A port can be refused on what you are buying rather than on you — flats above commercial premises, unusual construction, short leases.
• Ports are usually time-limited. If the sale and purchase do not complete together, or the gap runs beyond what the lender allows, the port can lapse.
• Check what the early repayment charge actually is in your own offer document before assuming porting is the cheaper path. Occasionally it is not.
• Arrangements to pay usually show. Anything agreed with a creditor during a difficult period is usually visible, even where it was the sensible thing to do at the time — though the pandemic payment deferrals and the 2023 Mortgage Charter options were deliberately kept off credit files, and lenders see those on statements anyway.

If the honest answer is that your existing deal is not worth preserving, I will tell you that, even though it is the shorter conversation.