It is common for leases of flats to prevent any structural alterations by the tenant. In practice though, many landlords usually allow such alterations to be carried out subject to licence and, in certain circumstances, the payment of a premium.
However, a recent case may have put a stop to this: Duval v 11-13 Randolph Crescent 2018. In this case, a freeholder was willing to waive the absolute prohibition against structural alterations in the lease and consent to the works being carried out by the tenant. But all leases in the block were in the same form and included a common mutual enforceability clause. It obliged the landlord to enforce any covenants entered into between him and a tenant at the request of any other tenant in the block.
The court held that consenting to structural alterations would be a breach of the absolute prohibition and this would amount to a breach of the mutual enforceability clause by the landlord. Therefore another tenant in the block could potentially have an action against the landlord.
Following this, a landlord may decide not to license anything that would otherwise be a breach of the lease for fear of having to defend claims from other tenants. It should be noted that a tenant must act reasonably and have a valid reason for objecting to the licence. A practical solution may be for the landlord to obtain consent from all of the tenants of a block prior to granting a consent of this type.
The position differs if alterations are prohibited subject to obtaining the landlords consent. In this circumstance, a landlord would be free to grant or deny consenRead More – Source