Porting Your Mortgage: Why It Is Not the Automatic Right You Think

Here is one of the most common misunderstandings in the whole of homebuying. People believe that because they already have a mortgage, taking it with them to the next house is automatic, a simple admin job, a right they have earned. It is not. Porting is treated as a brand new mortgage application, and like any application, it can be turned down, even if you have never missed a single payment.

What porting actually means

Porting lets you carry your existing rate and deal to a new property when you move. Technically your old mortgage is repaid and a new one is taken out, but on the same terms: the same interest rate, the same end date, the same early repayment charge structure. That is the real prize, because it means you avoid the early repayment charge that leaving your deal early would normally cost you.

So the rate ports. The lending does not port automatically. And that distinction is where people come unstuck.

Why it is not automatic: it is a full new application

Even though you keep your rate, the lender underwrites the whole thing again from scratch. Expect all of this:

• Documents and income. Payslips, bank statements, proof of income, the lot, just like a first application.
• A credit check. A fresh look at your credit file as it stands today.
• An affordability assessment. Crucially, against the lender's current rules, not the ones that applied when you first borrowed. Lending has tightened a lot over the years.
• A valuation or survey of the new property. The lender has to be happy to lend against the new home, which is a different property with its own risks.
• Legal work. Conveyancing to move the charge onto the new property, the same as any purchase.

Any one of these can stop a port in its tracks. Pass them all and you keep your deal. Fall short on one and the answer can be no.

Where porting trips people up

• Affordability has moved. If your income has dropped, you have changed jobs, gone self-employed, or had a baby and your outgoings have risen, the affordability sums can fail even though your rate would have stayed the same.
• The new property does not suit the lender. An unusual construction, a flat above a shop, a short lease or a high-rise can all fall outside a lender's criteria, so the port is refused on the property, not on you.
• You need to borrow more. The top-up is a separate product, covered next.
• The timing does not line up. Porting usually needs your sale and purchase to complete on the same day, which is covered further down.

Porting and borrowing more: the two-part mortgage

Moving up the ladder usually means a bigger mortgage. When you port and need extra, the additional borrowing is a separate product at the lender's current rates, assessed on its own. You can end up with two sub-accounts on two different rates, ending on two different dates. And here is the sting: the lender can approve the port but decline the top-up, leaving you short on the new purchase. It is fully underwritten, exactly like new lending, because that is what it is.

Porting and borrowing less

Downsizing has its own wrinkle. If you port but only need part of your original loan, repaying the rest can trigger a partial early repayment charge on the bit you are giving back. Worth checking the numbers before you assume porting is free.

When porting is worth it, and when it is not

Porting earns its keep when you have a low rate with a meaningful early repayment charge to protect. Keeping that rate and dodging the charge can save thousands. But porting is not automatically the best move:

• If your current rate is uncompetitive, a brand new deal on a sharper rate can beat porting, even after any charge.
• If you have no early repayment charge, there is little to protect, so a fresh remortgage or a new mortgage on the move may simply be better value.

This is the same compare-both logic as choosing between a product transfer and a remortgage: the headline convenience is not always the cheapest answer.

The timing trap

Because you are repaying one mortgage and opening another on the same terms, a port usually needs your sale and your purchase to complete on the same day. If the chain slips and they fall out of sync, you can be left with a gap, a short bridging need, or in the worst case a port that no longer works. This is exactly the kind of thing that needs managing carefully, not left to chance.

How a broker helps

A whole-of-market broker checks whether your mortgage is portable in the first place, runs the real comparison (keeping your rate and saving the early repayment charge versus a fresh deal elsewhere), and handles the application and the two completions lining up. They will also spot early if the new property or your changed circumstances are likely to be a problem, before you are committed to a purchase that depends on it.

If you are moving and hoping to take your mortgage with you, the worst thing to do is assume it will just happen. Debbie at DS Financial checks portability, runs the numbers against the wider market, and manages the timing so a move does not fall apart over the mortgage. For the bigger picture, see our moving home guide and how early repayment charges work.

General information, not financial advice. Your home may be repossessed if you do not keep up repayments on your mortgage.

Sources: MoneyHelper, Porting a mortgage, FCA, Mortgages.