A letter written to the Sunday Times and London Evening Standard has been released by estate agent Marc von Grundherr.

In it, von Grundherr claims that the discount that shadow chancellor John McDonnell would hand private tenants under a new Right to Buy would be 20%.

While we have queried where this statistic has come from, we have not been able to establish where it originated.

McDonnell himself said when discussing the proposal – first mooted by Jeremy Corbyn – that the Government would set the rate.

Right to Buy in the social housing sector offers a 35% discount, but this can rise to 70% depending on how long the tenant has been in occupation.

The letter (which we have lightly edited) from von Grundherr, who is director of London agent Benham and Reeves, is as follows:

Dear Sirs

As our political parties squabble over our European future and the country sits in a state of political paralysis, note that our property market has retained dignity even if our politicians have not.

UK house prices and rental values are higher than before the referendum by 8% and 5% respectively, and whilst transactions in London in particular are now lower, much of this can be attributed to the assault on Stamp Duty orchestrated a couple of Chancellors ago where the top rate is now an asphyxiating 15%.

This is remarkable resilience overall, yet not content with successive attempts at destroying the market and sucking positive sentiment out of it, enter stage left the Labour Party with a nuclear option or two to finish the job that the Conservatives seem to have started.

Sadiq Khan wants to cap rents and therefore the investment yields that landlord investors may achieve.

John McDonnell says he wants to tax landlords until, presumably, their pips squeak. And now wishes to steal 20% of the value of each of their properties and gift that to their tenants with a neat bow attached.

If this short-sightedness succeeds in becoming law in the event of a change of administration, as now seems possible, the glee of the Treasury and tenants respectively will be very short lived when they suddenly realise that there are no landlords left to fight.

The property market underpins our economy, provides much of our social housing via the PRS, employs hundreds of thousands of people and contributes billions of pounds in direct and indirect taxation.