Buy to Let Turns 30. £311.6bn Outstanding, and It Is Now a Refinancing Market

The buy to let mortgage is thirty years old this year. Research published by Paragon Bank in September 2026 puts outstanding buy to let lending at £311.6bn across 1.92 million mortgages, roughly a fifth of all outstanding mortgage balances in the UK.

New lending in 2025 came to £40.3bn.

Put those two together and you get the shape of the market. The stock is large and it turns over slowly. Most of what happens in buy to let now is existing loans being refinanced, not new landlords arriving.

What that changes

Thirty years ago the growth story was expansion. England's private rented sector went from under two million households to nearly five million, about one in five homes.

That phase is over. The sector is not shrinking, but it is not compounding either. Which means the event that determines most landlords' returns is no longer the next purchase. It is the next product end date.

That is a less exciting thing to plan for and a more consequential one. A portfolio of six properties has six of those dates, and if they were all taken at the same time they all land at once.

The arrears figure runs against the usual story

There is a persistent assumption that landlords are the overstretched end of the mortgage market. The data does not support it.

The proportion of buy to let mortgages in arrears has been lower than the owner occupier equivalent in every year since records began, with a single exception. That is thirty years of evidence pointing the other way.

It makes sense when you think about how the lending is assessed. Rental cover is tested against a stressed rate, and interest only is common, so the payment is usually a smaller share of the income supporting it than on a residential mortgage.

Where it gets harder

None of the above describes a market that is simple to borrow in. A £311.6bn stock spread across 1.92 million loans is a mature market, and mature markets segment. Limited company structures, houses in multiple occupation, holiday lets, portfolio cases above a certain number of properties and non resident applicants are each assessed on their own terms, and the terms differ.

Average rent of £1,400 a month, per the ONS release of 16 September 2026, tells you very little about whether a particular property in a particular structure will support a particular loan.

Tax treatment of any of these structures is a matter for a qualified tax adviser.

Thirty years in, the product is ordinary. Getting the right one is not.

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Sources

• Paragon Bank, analysis marking 30 years of buy to let lending, published September 2026
• Office for National Statistics, Private rent and house prices, UK, released 16 September 2026