Meanwhile, Norwich was the biggest climber, rising from 21st place in 2020 to 10th this year.

Luke Savins, of William H Brown lettings agents in Norwich, said: “Properties get 20 or 30 inquiries in the first couple of days of marketing. We are having to limit viewings.” Supply is exceptionally low. “Excluding the student market, we have 19 available properties to let. Normally we would have 40 or 60,” said Mr Savins.

Rising house prices mean many landlords have taken the opportunity to sell up and exit the market on a high, said Mr Savins. Meanwhile, rising rents, which have jumped by 10pc year-on-year, have deterred tenants from moving.

In Norwich’s so-called “golden triangle” between Unthank Road, Earlham Road and the University of East Anglia on the western side of the city, which is a hotspot for young professionals, rental prices of some homes have climbed by 35pc in two years, said Mr Savins. A house that let for £800 per month in 2019 was just rented out for £1,100.

A quarter of tenants are relocating from the likes of London and Cambridge, because the cost of living in Norwich is lower and they no longer need to be in the office every day, said Mr Savins. Some businesses have relocated too, and there many strong local employers, including two universities, four hospitals within commuting distance, and Aviva insurers.

In Oxford, Steven Sarbatta, of Connells estate agents in Cowley, said renters moving to the city from places such as London and Birmingham account for a tenth of tenant demand.

But many tenants work locally in the science and business parks around Kidlington, which is also home to Oxford Airport, said Mr Sarbatta. Properties that have good access to the A34 are therefore particularly popular.