So-called ‘real rents’ - those adjusted for inflation - have fallen by 2.2 per cent since October 2008.
This means that the average cost of living has far outstripped average rents.
The claim comes from Countrywide’s high end brand Hamptons International, which monitors the rental market.
In the last 10 years the consumer price index, which measures the average cost of goods and services, has outpaced rents.
Over the last decade rents have actually risen 22 per cent but inflation has risen 24 per cent over the same period.
The East and London are the only regions across Great Britain where rental growth has outpaced inflation.
In the East, real rents have risen 7.5 per cent over the last 10 years. Meanwhile in London, real rents are up a mere 0.5 per cent since October 2008.
However, inflation has outpaced rental growth in all other regions across Great Britain, resulting in negative real rental growth.
The Midlands has seen the biggest fall in real rents, down 7.8 per cent since October 2008; real rents in the North have fallen 6.9 per cent as inflation has outpaced rental growth.
Aneisha Beveridge, Hamptons International’s head of research, says: “Real rents in Great Britain have been falling for the last 21 consecutive months. This comes as a result of sluggish rental growth and a post-EU referendum backdrop of rising inflation.
“However, this could be set to change as inflation begins to fade and rental growth starts to pick up pace. Currently the East and London are the only regions where real rents have risen over the last decade.”