Thank you for the above. Unfortunately, based upon what you say, your father may have fallen into a common trap and created inadvertently and implied periodic tenancy with protection under part two of the landlord and tenant act which gives the tenant security of tenure in that they have a right to renew the lease on commercial terms.
In order to bring the tenancy to an end, your father would need to sell something called a section 25 notice which is a formal statutory notice notifying the tenants that they are required to move out in six months or more. Your father can only server section 25 notice however if you can show that he has a statutory ground to do so if a protected tenancy exists. The grounds are as follows:
Premises are in disrepair
Arrears of rent
Other breaches of covenant
Suitable alternative accommodation
Tenancy was created by a sub-letting
Landlord's intention to redevelop
Landlord's intention to occupy
based upon what you say, your father may have grounds for seeking possession of the premises on the grounds that he intends to redevelop the same however this ground only covers redevelopments which involve an element of substantial demolition. Mere conversion works are not covered. It is not intending to substantially demolish the premises in order to build residential property, he will need to attempt to rely upon one of the other conditions such as disrepair,, or that he is willing to secure alternative accommodation for the partnership.
Before serving notice, your father would do well to consider contacting a local solicitor to act for him. It may be possible to avoid an implied secure tenancy but based upon what you say, I think the chances of that are likely to be slim. Failing that, there is nothing preventing your father informally negotiating with the GP partners or failing which, if the rent is not a commercial rent, your father could look to increase the rent to a commercial level which may encourage the partnership to leave voluntarily if it becomes unaffordable.
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