A drop in demand for properties across the capital has meant that the balance of power has moved towards tenants and away from landlords.
In recent years, the prices of property to rent in the capital in particular have continuously gone up and up thanks to the fact that those who were trying to get a foot on the ladder could not secure finance to buy homes without a massive deposit.
However, supply now outstrips demand thanks to the ease with which landlord insurance customers have been able to secure funding, and the appetite that has spawned from the health of the private rental sector.
Throughout 2012, Chesterton Humberts reports, the number of mortgages approved for landlords grew by a full 19 per cent as more and more saw the benefits of moving into this market as a long term investment.
This has meant that rental prices have decreased, with the data from the organisation saying that the average cost of a monthly tenancy has fallen by 1.7 per cent in the first months of 2013.
It expects these to remain somewhat subdued over the next few months, with moderate rises likely to come in the second six months of 2013, predicted to be around two to four per cent overall.
What the oversupply has meant for landlords though is that tenants have now been placed once more into a strong position where they feel they can negotiate the prices that they pay on a monthly basis, something that they have not been able to do when prices were continuously on the rise.
"Many landlords are now being more flexible when it comes to rent reviews with existing tenants, on the basis that it is better to retain a good tenant who pays their rent and looks after the property than deal with the hassle and expense of filling a void with a new and unknown tenant," said Nick Barnes, Chesterton Humberts' head of research.