You must be a long leaseholder of a flat, or maisonette, (that is, in excess of 21 years when first granted) and have owned the property for at least 2 years. (Residence is not necessary).
The right is exercisable against most landlords, be they private, council or housing association. A shared ownership leaseholder is not classified as holding a long lease unless they have “staircased “up to 100% ownership .However the Housing Association may still be prepared to extend the lease anyway ,you should check with your landlord on their policy..
Certain properties are excluded from the right to a new lease. These include National Trust properties and Crown property, although the latter may still be prepared to follow the Act as if it applied to them.