The landlord may not give notice under section 173 before the end of the period of six months starting with the occupation date of the contract.
If the contract is a substitute occupation contract, the landlord may not give notice under section 173 before the end of the period of six months starting with the occupation date of the original contract.
For the purposes of subsection (2)—
(a) an occupation contract is a substitute occupation contract if—
(i) the occupation date of the contract falls immediately after the end of a preceding occupation contract,
(ii) immediately before the occupation date of the contract a contract-holder under the contract was a contract-holder under the preceding contract and a landlord under the contract was a landlord under the preceding contract, and
(iii) the contract relates to the same (or substantially the same) dwelling as the preceding contract, and
(b) "original contract" means—
(i) where the substitute occupation contract has an occupation date falling immediately after the end of a contract which is not a substitute occupation contract, the occupation contract which precedes the substitute occupation contract;
(ii) where there have been successive substitute occupation contracts, the occupation contract which preceded the first of the substitute occupation contracts.
This section is a fundamental provision which is incorporated as a term of all periodic standard contracts, except periodic standard contracts which—
(a) do not incorporate section 173 as a term of the contract, or
(b) are within Schedule 9 (whether or not they incorporate section 173 as a term of the contract),
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