Speaking today, Reeves said property income tax would rise by 2% across basic, higher and additional rates, taking these to 22%, 42% and 47%, respectively.

This will raise around £500million a year in extra tax, according to an accidentally-published document from the Office for Budget Responsibility (OBR) this morning.

The OBR said this would end up being passed on to tenants in the form of higher rents, but that it would be offset by increased downward pressure on house prices.

Hamptons head of research Aneisha Beveridge said: “Those operating through limited companies will remain unaffected, but for individual landlords who make up the bulk of the market and who are already squeezed by higher borrowing costs and previous tax changes, this could accelerate the trend of investors exiting the market.

“Over time, that risks reducing rental supply and pushing rents higher.”

Elsewhere, owners of properties worth more than £2 million will be hit by a new “mansion tax” that will net the government £400 million by 2031, the Chancellor confirmed today.