Homeowners who let out their properties last year rather than sell them for a cut price are being forced to reduce rents or risk losing their tenants as the market rapidly sours.

Letting agents saw a rush of so-called "accidental landlords" into the market last year, as falling house prices convinced property vendors to delay their sales. But the sheer volume of properties that have become available to potential tenants in recent months has brought stiff competition for landlords and put pressure on rents.