Generally, no: for a standard private tenancy, a landlord cannot require more than one month’s rent as a deposit, and cannot demand a second deposit for the same tenancy simply because the rent has increased. The total amount requested at the start of a tenancy is generally capped at two months’ rent: one month’s deposit and one month’s rent in advance, subject to limited exceptions. Ask the landlord to explain any further payment in writing, and do not assume it is lawful without checking the specific circumstances. You can contact the RTB or seek advice from a qualified housing adviser or solicitor if there is a dispute.