The case law on specific performance and injunctions is rich and fact-sensitive. A handful of leading decisions establish the contours of the discretion and the application of the bars.
Lumley v Wagner (1852) is the foundational authority on the use of negative injunctions in personal service contracts. The defendant, an opera singer, had contracted exclusively to sing at the plaintiff's theatre and not to sing elsewhere during the contract term. She breached the agreement to sing for a rival. The court refused specific performance of the positive obligation to sing (personal services) but granted an injunction restraining her from performing elsewhere. Lord St Leonards LC reasoned that the negative stipulation was separate and could be enforced without indirectly compelling the positive performance. This decision established the Lumley v Wagner principle: a prohibitory injunction may enforce a negative covenant even in a contract for personal services, provided it does not have the practical effect of forcing the defendant to perform the positive obligation.
The scope of Lumley v Wagner was refined in Warner Brothers Pictures Inc v Nelson [1937] 1 KB 209, where Bette Davis was restrained from working for another film studio in breach of an exclusive-services contract. Branson J granted the injunction but limited its duration and geographical scope to avoid the oppressive effect of leaving the actress with no practical alternative but to work for the claimant. The balance between protecting the employer's legitimate interest and avoiding indirect servitude is delicate; modern courts scrutinise such injunctions carefully.
Page One Records Ltd v Britton [1968] 1 WLR 157 illustrates the limits of the Lumley principle. The defendants, a pop group (The Troggs), sought to terminate their management contract. The manager sought an injunction restraining them from engaging another manager. Stamp J refused relief, holding that the injunction would in effect compel the group to continue employing the plaintiff as manager or cease performing altogether, tantamount to indirect specific performance of a personal services contract requiring mutual trust. The case shows that even negative stipulations will not be enforced by injunction if the practical consequence is to compel positive performance.
Ryan v Mutual Tontine Westminster Chambers Association [1893] 1 Ch 116 established the supervision bar. The landlord's covenant to provide a porter was not specifically enforceable because compliance could not be objectively determined without continuous judicial oversight. Lord Esher MR emphasised that equity does not make orders that require the court 'to do a thing which is impossible.'
But in Posner v Scott-Lewis [1987] Ch 25, Mervyn Davies J distinguished Ryan and granted specific performance of a landlord's covenant to employ a resident porter. The obligation was sufficiently precise: the landlord merely had to appoint a named individual to reside on site. Compliance was ascertainable objectively, and constant supervision was not required. The decision suggests that the supervision bar is not absolute but depends on the nature and precision of the obligation.
Co-operative Insurance Society Ltd v Argyll Stores (Holdings) Ltd [1998] AC 1 is the leading modern authority on the supervision bar and the limits of specific performance in commercial contracts. The defendant operated an anchor supermarket in a shopping centre. It closed the store in breach of a covenant to keep it open during usual trading hours. The landlord sought specific performance. The Court of Appeal granted the order, but the House of Lords reversed. Lord Hoffmann delivered the principal speech, identifying several objections: difficulty of framing a sufficiently precise order; the need for ongoing supervision; the risk of wasteful litigation over compliance; and the potential injustice of compelling the defendant to carry on a loss-making business on pain of contempt. His Lordship acknowledged that damages might undercompensate (the landlord's loss was the diminution in value of the centre and surrounding units) but held that the settled practice not to order a defendant to carry on a business reflected sound policy. Co-operative Insurance reaffirms judicial caution in expanding the scope of specific performance beyond traditional boundaries.
Patel v Ali [1984] Ch 283 illustrates the hardship bar. The vendor, who had contracted to sell her house, was subsequently diagnosed with cancer, lost a leg, and had three young children. The purchaser sought specific performance several years after the contract. Goulding J held that, although the vendor was in breach, specific performance would cause hardship grossly disproportionate to any advantage to the purchaser, who could be compensated in damages. The decision underscores that equity remains responsive to individual circumstances and that the discretion to refuse relief is real, not merely formal.
Finally, Sky Petroleum Ltd v VIP Petroleum Ltd [1974] 1 WLR 576 exemplifies the flexibility of equitable relief in commercial emergencies. During the 1973 oil crisis, the defendant threatened to terminate a long-term supply contract. The claimant obtained an interlocutory mandatory injunction requiring continued supply, on the ground that damages would be inadequate (no alternative supply was available and the claimant would be forced out of business). Goulding J treated the injunction as akin to specific performance, acknowledging that the remedy was exceptional but justified by the unique circumstances. The case shows that, notwithstanding general reluctance to compel continuous performance, the court retains discretion to grant relief where justice demands.