House prices and rents in the same area can move in different directions for extended periods. They are set by different mechanisms and constrained by different things.
Prices are financed and rents are not
A purchase is usually funded by a loan, so what a buyer can offer depends on interest rates, deposit size and lending criteria as much as on income.
When borrowing becomes cheaper, the same income supports a larger loan, and prices rise without anyone earning more.
Rent has no such lever. It is paid from current income each month, which anchors it to wages in a way that sale prices are not.
Contracts delay the adjustment
A sale price is agreed at a single moment and reflects conditions in that week.
Rents are fixed for the length of a tenancy, so most of the rental stock is priced according to conditions that prevailed months or years ago.
Market movements therefore reach rents gradually, appearing only as tenancies end and properties are re-let, which is why published rent indices lag visible market shifts.
Expectations enter prices and not rents
A buyer is purchasing future housing services and a future resale, so beliefs about where prices are heading feed directly into what is offered today.
A tenant buys only the coming months, and no expectation about next year's market changes what this year's flat is worth to them.
This is why sale prices can rise sharply while rents are flat: the change is in expectations rather than in the underlying use of the building.
Supply responds on different timescales
New construction adds to both markets, but it takes years to arrive and is small relative to the existing stock.
The rental supply also moves through conversion, as landlords buy or sell and owners let properties they cannot sell at the price they want.
That switching partly links the two markets, which is why a sustained divergence eventually pulls investors in or out and narrows the gap.
The yield connects them in the end
The relationship between annual rent and purchase price is the return an investor receives, and it is the number that ties the two series together.
When prices rise faster than rents, that return compresses, and buying to let becomes less attractive relative to other uses of the money.
Reduced investor demand then slows price growth, while the rental supply tightens and rents catch up, which is the correction that follows a long divergence rather than a prediction about any particular market.