AFixed Term tenancy describes a tenancy with pre-established start and end dates.
This in in contrast to a periodic tenancy which continues on a month by month basis following the end of the fixed term, without the requirement to renew the tenancy.
The initial fixed term of a tenancy can be as little as say six hours, but the landlord could not legally enforce any eviction if the tenant decided he wished to remain for say six months.
Meantime any pre-arranged subsequent tenants would be prevented from occupation – such extended tenancy could legally last 6 months.
There are ways to motivate tenants to stick to the original term agreed. By providing in the contract that the rent increase 10 times the original rent should the tenant leave after the end of the fixed term agreed.
So although the landlord would be unable to evict the first tenants or accommodate the new tenants for at least six months, he could sue the overstaying tenants for the additional rent.
This additional rent might enable the landlord to accommodate the disappointed second group of tenants e.g. in a hotel – assuming the landlord is successful in suing the late leaving first group of tenants