Whether or not there is an express provision in the lease, landlords are required to give their tenants ‘quiet’ and uninterrupted use of the premises for the duration of the term of the lease.
Additionally, landlords must ensure that they do nothing to derogate from (i.e. nothing that is inconsistent with) the grant of the lease of the property to the tenant. Should a landlord be forced to close a shopping centre or a multi-occupied office building or business park, one can see that their tenants could reasonably argue that, by being deprived of access to the premises, the landlord is acting in a way that is inconsistent with the lease – indeed, the landlord is preventing the tenant from accessing the subject matter of the lease.
On the face of it, these circumstances would give rise to a claim for breach of both the covenant for quiet enjoyment and the covenant not to derogate from the landlord’s grant. Such a claim might ordinarily result in the court granting an injunction to compel the landlord to remedy the breach and compensation might be awarded to the tenant for loss of trade and/or to compensate the tenant for all or part of the rent that they have paid for that period. Alternatively, such breaches could amount to repudiatory breaches which would allow the tenant to argue that the lease is terminated and to claim damages. But in the event of a forced closure (presumably as a result of legislation) the landlord would be acting in accordance with statute (and therefore lawfully) and have a complete defence to such claims. Only if the landlord has chosen to close the shopping centre/retail park/office building/business park (i.e. it is a voluntary measure) could the tenant have a claim.
Assuming the landlord has simply reacted to a new statutory requirement, the tenant will need to consider other remedies.