Report Backdated Rent Increase in All about renting Posted September 3, 2007 You've got to be joking! On no account would I pay a back dated increase in rent, though if it was reasonable would certainly agree to pay it pro rata from the date of notificiation. This is something that should have been sorted out by the agent before the end of the contract, not three months after. Would you pay if they happened to mention it to 12 months after the date? Then why would you pay it after three months? A sudden bill for £150 could cause significant hardship for some. I'm sure the owners wouldn't be impressed about all those expensive fees they pay the agent for this level of service - I suspect the agent is trying to hide his mistake from the owner without eating into his profits.