Before making a possession claim on the ground in section 170 the landlord must give the contract-holder a possession notice specifying that ground.

The landlord may make the possession claim on or after the day on which the landlord gives the contract-holder the possession notice.

But the landlord may not make the possession claim after the end of the period of six months starting with that day.

The landlord may not give the contract-holder a possession notice specifying the ground in section 170 after the end of the period of two months starting with the date specified in the notice under section 168 as the date on which the contract-holder would give up possession of the dwelling.

This section is a fundamental provision which is incorporated as a term of all periodic standard contracts.