Firstly, we assume that you are referring to a statutory renewal, as otherwise the parties would be free to agree the terms of a new lease as they choose. Residential lease extension If you are referring to a residential lease, we assume that it is to a lease extension of a flat under the Leasehold Reform, Housing and Urban Development Act 1993 (LRHUDA 1993) (rather than a lease extension of a house under the Leasehold Reform Act 1967). LRHUDA 1993, s 7(9) provides: Where any person— (a) is a third party to the existing lease, or (b) (not being the landlord or tenant) is a party to any agreement collateral thereto, then (subject to any agreement between him and the landlord and the tenant) he shall be made a party to the new lease