Tillman v Egon Zehnder [2019] UKSC 32: what it changed about UK sales restrictive covenants

The Supreme Court's 2019 decision in Tillman v Egon Zehnder Ltd [2019] UKSC 32 restated UK law on the severance of unenforceable provisions in restrictive covenants. For UK sales hires the case is foundational: it changed how the 'blue-pencil' doctrine applies and what employers can recover from over-broad covenant drafting.

This piece is a practitioner walkthrough of what Tillman decided, what it changed, and what UK sales-side practice should look like in 2026.

What the case decided

Mary-Caroline Tillman was a senior employee at Egon Zehnder, an executive search firm. Her contract included a non-compete restricting her from being 'directly or indirectly engaged or concerned or interested in' any competitor for six months post-termination. She left and joined a competitor; Egon Zehnder sought an injunction.

The Court of Appeal held the words 'or interested in' were too wide (they would prevent the employee from holding even a small shareholding in any public competitor) and therefore the entire non-compete was unenforceable. The Supreme Court reversed: the offending words could be severed under the 'blue-pencil' test, and the remainder of the covenant was enforceable.

The Court restated the test for severance:

1. The unenforceable provision must be capable of being removed without the necessity of adding to or modifying the wording of what remains.
2. The remaining terms must continue to be supported by adequate consideration.
3. The removal of the unenforceable provision must not so change the character of the contract that it becomes 'not the sort of contract that the parties entered into at all'.

This restatement is the modern UK position on covenant severance.

What it changed

Pre-Tillman, employers were uncertain whether over-broad drafting in any limb of a covenant would render the entire covenant unenforceable. Some Court of Appeal authority suggested it would. Tillman confirmed it does not, provided the three conditions above are met.

The practical effect for UK sales-side employment law:

Employers: gained back some lost ground. Over-broad drafting of a single limb (e.g. 'any competitor anywhere in the world') no longer automatically kills the entire covenant if the offending limb can be cleanly severed.

Employees: lost some defensive scope. The argument 'the covenant is too wide therefore wholly void' is harder to run successfully in 2026.

Drafters: the message is mixed. Severance is available but courts continue to scrutinise whether the three conditions are met. Drafters who rely on severance to save sloppy drafting risk having entire covenants struck down where the offending wording isn't cleanly removable.

How it applies to UK sales restrictive covenants

Sales restrictive covenants in 2026 typically include:

• Non-compete (prohibition on working for named competitors or in a similar role)
• Non-solicitation of clients
• Non-solicitation of staff

Each can have one or more over-broad limbs. The Tillman doctrine means a non-compete that, for example, prohibits work for 'any business competing with the employer in the UK or any other jurisdiction' might have 'or any other jurisdiction' severed and the UK-only restriction enforced. A non-solicitation covering 'any client of the employer' might have its scope narrowed to clients the employee actually worked with.

The defensive position from the employee side: argue that the offending wording cannot be cleanly severed because removing it changes the character of the covenant. The further the offending limb sits from the bargain the parties intended, the stronger this argument.

What strong drafting looks like in 2026

Three principles for UK sales contract drafters post-Tillman:

1. Draft each limb at the boundary, not beyond it. Drafting that intends to be saved by Tillman severance is dangerous. The cleaner approach: draft what is reasonable and stop.

2. Make limbs structurally separable. Where multiple restrictions are bundled into one limb, courts may find them inseparable. Where each restriction sits in its own clause with its own consideration, severance is cleaner.

3. Document the legitimate proprietary interest the covenant protects. Severance addresses scope; reasonableness addresses whether the covenant is enforceable at all. The Office Angels test (legitimate proprietary interest, no wider than reasonably necessary) sits alongside Tillman, not instead of it.

What to operationalise

For UK sales employers:

• Audit existing employment-contract restrictive covenants. Where covenants are over-broad in ways severance might not save, redraft at next hiring round.
• Document the legitimate proprietary interest each covenant protects in the contract preamble or accompanying letter.
• Train hiring managers on the difference between aspirational covenant drafting and enforceable drafting; the former routinely produces unenforceable contracts.

For UK sales employees:

• Read your covenant carefully at offer stage. Negotiate scope narrower if necessary. Tillman makes it harder to argue an over-broad covenant is wholly void post-departure; pre-signing negotiation is the cleaner path.
• If your covenant is challenged in litigation, the severance question matters as much as the reasonableness question. Specialist employment counsel for any covenant dispute.

This is editorial coverage of UK case law, not legal advice. Consult an employment solicitor for your specific covenant.