In the first news from real estate firm Savills, landlords have made £177bn in capital growth from their portfolios in the last five years - and that's without taking into account rental income.
The firm says the lack of new houses being built and growing demand from tenants for property is pushing up house prices as well as rents.
The result is, says Savills, that buy to let landlords have been the biggest winners of a rocketing house prices.
Value of the BTL sector rockets
Indeed, the value of the private rented housing sector is now worth more than £1trillion, a rise of 57% since 2008 when the financial crisis first struck.
Savill's residential research director, Lucian Cook, said more should be done to encourage houses to be built to correct the rental market's undersupply.
The value of housing stock owned by landlords has risen from £359bn in 2002 and now stands at £1.159bn.
This also means that housing anything payments which are paid to private landlords have also risen from £3.4 billion in 1998 to £9.3 billion last year.
The National Landlords' Association (NLA) has also revealed that the number of people living in private rental accommodation has nearly doubled over the past 10 years from 10% to 18%.
They are now predicting that in the coming years this figure will grow to 25% - and even possibly up to a third.
Landlords use BTL finance
The NLA's figures reveal that around 1 million landlords in the UK are using BTL finance with the average annual cost of mortgage repayments being £20,950.
However, landlords with a portfolio of between one and four properties repaid an average of £10,335 on their mortgage whereas those with larger portfolios, that's having 11 properties or more, repaid £55,285.
The NLA's chairman, Carolyn Uphill, said: “Private investors are supplying well maintained homes when governments have failed to stimulate or incentivise more social housing.
“There's no sign these issues will improve so it's no wonder that BTL lending is running at an all-time high.”
However the NLA is also warning landlords that they should prepare now for any future interest rate rises and they have published new guidance on what the potential effect may be on their business.
The guidance on what to do when interest rates do rise and their effect on BTL borrowing is part of their latest Rent Risk Resolve campaign.
