No. Some leases will specifically state that the tenant does not have the protection of the Landlord and Tenant Act 1954, which normally provides for security of tenure. As a general rule, you should be very wary of giving up the security of tenure that the law normally provides. However, there will be some cases where a landlord will not be prepared to sign a lease except with this exclusion. Even where you do have security of tenure, that shouldn’t be taken as gospel as a landlord might wish to redevelop or sell the property at the end of your lease period, for example.