Landlords were unable to drop rents so radically, he said.
Those are the people who are getting serious, the real estate agents say, dropping rents and making concessions.
Even as prices begin to stabilize or drop, rents remain higher than they were two or three years ago.
The tax benefits are typically far smaller than the amount of money landlords could lose by dropping rents to stabilized levels.
This might mean subdividing larger units, dropping rents, or just ensuring spaces are equipped with a decent broadband connection and parking.
Karen Buck, the Labour MP who was passed the letter, said it showed that ministers were wrong when they claimed nobody would need to move as landlords would drop rents to accommodate welfare cuts.
They went on to calculate that it would take about 74,000 Wall Street job cuts in New York to tip the scales to the point where landlords at New York's highest-quality Class A buildings are forced to drop rents significantly.
But in the 1890s the company cut wages without dropping rents, inciting massive strikes, unionization at the hands of a man who would become America's leading socialist, and boycotts that shut down rail service around the midwest.
But councils say the demand for private rented property from tenants priced out of the housing market means most landlords see no reason to drop rents, and a substantial number say they will no longer consider renting to people who are claiming housing benefit.
