This is a pre-agreed amount of money retained as a contingency fund from a landlords rent and held in the client account until an emergency occurs. This enables letting agents to quickly effect urgent maintenance, without delay: like a boiler or roof repair or washing machine replacement. Such unpredictable repairs are inevitable but the adverse effects can be mitigated by being prepared. Cleared funds must be in an agents client account prior to ordering such works to comply with letting rules. The logic of this is obvious – waiting for a landlord to transfer funds in the middle of winter when the tenants are freezing awaiting a boiler repair is avoided by a retention!