Unfair dismissal definition of SOSR for — refusal to accept new terms: use the right test.

William Slivinsky
Sep 24
8 min read

Under the unfair dismissal definition in UK law, “some other substantial reason” (SOSR) may include dismissal for refusing a contractual change—like a pay cut, rota move, or new duties. Iportant to know is the tribunal doesn’t ask whether you were “reasonable to refuse it.” It is a question whether the employer acted reasonably in treating your refusal as the sufficient reason to dismiss you under s.98(4) ERA. Two real-case anchors—Garside & Laycock v Booth and Catamaran Cruisers — both explain how judges balance a stated business reason against employee impact and workable alternatives.

This article delves deeper into general advice "Usually, the employer and employee both need to agree to any contract changes. But an employee can insist on a change if they have a legal right to it." Why UDO writes about it ? Because in some cases, when you refuse the change, your employer may reach out for SOSR and get you dismissed.

Unfair dismissal definition of SOSR in the context of refusing change in you contract - What you’ll learn

Unfair Dismissal Definition in SOSR cases (quick recap)
Case snapshot — Garside & Laycock v Booth
The Catamaran balance: how tribunals weigh things
Process markers that matter (2024 Code, timing, specificity, options tested)
Evidence to ask for (business case note, Q&A log, options table)
Impact proofing (childcare, priority-bills budget, health, travel)
Decision path & templates (pressure-test and copy-ready prompts)
2024 Statutory Code essentials (award adjustments up to ±25%)
Common pitfalls to avoid (misframing, mixing SOSR with re-engagement, EDT/time limits)

Unfair Dismissal Definition in SOSR cases (quick recap)

SOSR is a potentially fair reason under definition s.98(1)(b) ERA.
If your employer passes this first test, the tribunal then applies s.98(4) ERA: did the employer act reasonably in treating your refusal as SOSR and believe it was sufficient to dismiss you, considering its size/resources and circumstances and substantial merits?
The question is not whether you were reasonable to refuse; the focus is on the reasonableness of the employer’s decision to dismiss.

Case snapshot — Garside & Laycock v Booth

The employer proposed a 5% pay cut. Most staff accepted; Mr Booth declined and was dismissed (he did not re-engage). The ET asked the wrong question—whether he was reasonable to refuse. The EAT corrected the approach: the tribunal must assess whether the employer acted reasonably in dismissing for SOSR in all the circumstances—consultation, business evidence, alternatives, and individual impact. The EAT also reiterated the Catamaran point: a “sound, good business reason” can support SOSR, but the dismissal still has to fall within the band of reasonable responses. The appeal was allowed and the case remitted to the ET—not because the employer had to prove desperate, survival-level reasons (it doesn’t), but because the ET had applied the wrong test.

The Catamaran balance: how tribunals weigh things

Think in three lanes the tribunal will weigh together:

Business reason lane — What was the employer’s stated reason and what evidence supported it (data, demand, scheduling)?
Impact lane — What disadvantages did the change create for you (childcare windows, priority bills, disability/health, commute time/cost)?
Alternatives lane — Which options were explored (trial periods, phased implementation, team swaps, time-limited change, redeployment) and why they were accepted/rejected.Decision ask: even with a sound reason, did dismissal sit inside a reasonable band once all three lanes are weighed?

Process markers that matter (2024 Code, timing, specificity, options tested)

To move the dial, focus on how the decision was reached:

Timing: Was dismissal raised too early in discussions?
Specificity: Did you receive concrete information (what’s changing, why, for how long, and the numbers behind it)?
Options tested: Were workable alternatives genuinely considered, piloted, or costed—and are reasons recorded?
Participation: Were questions answered, meetings minuted, and outcomes adjusted when better options emerged?

Evidence to ask for (business case note, Q&A log, options table)

Request items that make the tribunal’s job easier:

A short business case note (1 page): what/why/who/when, duration, and data relied on.
A Q&A log: your questions, their answers, and documents shared.
An options table: alternatives considered (trial, phased change, redeploy, swap), quick cost/feasibility, and reasons for decisions.
Consistency notes: who accepted/declined, outcomes for each, and any comparators.

Impact proofing (childcare, priority-bills budget, health, travel)

Bring the real-world effect into view:

Childcare window: show nursery/school times; propose a 15–30 minute offset or fixed anchor hours.
Priority-bills budget (one page): Net pay → essentials (rent, utilities, food, travel) → shortfall £__ after change.
Health/disability: identify the adjustment (e.g., fatigue limits) and show the clash with the new terms.
Travel spike: old vs new commute minutes/£; weekly delta £__ with receipts or route timings.

Among other things, such as overlooking health and safety, you can learn how to use this in your situation.

Decision path & templates (pressure-test and copy-ready prompts)

One-minute decision path:

Documented business evidence? If it’s thin or keeps shifting, note that.
Real chance to influence the outcome? (Information shared early enough, questions answered, meetings minuted.)
Alternatives considered? Trialled, phased, redeployment/team swaps—and recorded reasons for rejecting.
Individual impact evidenced? Childcare windows, priority-bills budget, health/adjustments, travel time/cost.
When was dismissal first raised? If raised unreasonably early, record it.

Process focus: Consider the whole process—what’s in writing and what you’re told in group and 1:1 consultations. Keep a dated note of informal comments.

Important: If your employer signals “fire and re-hire” at the very start, that can count against reasonableness—the Statutory Code expects dismissal/re-engagement to be a last resort after genuine exploration of alternatives. It’s not automatically unlawful on its own, but it can evidence unreasonable process.

You should ask whether your employer has taken advice from Acas and to confirm how they’re complying with the Statutory Code on Dismissal & Re-engagement (e.g., early information, meaningful consultation, alternatives).

Where a change can be achieved by mutual agreement, say so explicitly. (Note: ERA 1996 s.4 is about updating the written statement of particulars when terms change; it doesn’t itself create a mutual-agreement route. The lawful route is: agree a variation by consent, or, if not, the employer must justify any SOSR dismissal and re-engagement as reasonable under s.98(4).)

Copy-ready prompts

Evidence prompt to employer (ask for what matters)

Please share a concise business case (one page) setting out what is changing, why, duration, and the data relied on. Please also provide a Q&A log of questions raised and documents shared, and an options table covering alternatives considered (trial/phasing/redeployment/swaps), any pilots, and reasons for decisions.Finally, please explain mitigations for colleagues with fixed childcare responsibilities or health-related adjustments.

Under-protest confirmation (if you remain in role during consultation)

I will continue working under protest while we explore alternatives. This is not agreement to a permanent change to my contract.

Budget exhibit line (attach to your representations)

After the proposed change, my monthly priority-bills shortfall is £__ (rent £, utilities £, food £, travel £). A trial or phased option would avoid this impact and should be considered before dismissal.

Mutual-agreement route (when you’d accept a limited change)

I am willing to agree [state the limited variation] on a [trial/time-limited] basis. Given that a consensual route is available, dismissal and re-engagement should not be used. Please confirm you will proceed by agreement and provide updated written particulars accordingly.

Early-threats note (if dismissal is raised too soon)

You have raised dismissal/re-engagement at an early stage. The appropriate approach is to provide the business case and genuinely explore alternatives first. Please confirm the steps you will take to consult properly and the alternatives you will assess before considering dismissal.

2024 Statutory Code essentials (award adjustments up to ±25%)

The Statutory Code on Dismissal & Re-engagement applies to terms-change scenarios and emphasises early information, meaningful consultation, exploring alternatives, and treating dismissal/re-engagement as a last resort.
Tribunals must consider the Code. Unreasonable non-compliance can lead to adjustments to certain awards (up to ±25%, depending on who was at fault).
Use the Code to frame process arguments; it supports (not replaces) the s.98(4) reasonableness test.

Common pitfalls to avoid (misframing, mixing SOSR with re-engagement, EDT/time limits)

Misframing: centring the case on “I was reasonable to refuse” rather than “the dismissal decision fell outside the band of reasonable responses.”
Mixing routes: where there’s actual dismissal and re-engagement, additional mechanics (EDT, rights-reserved acceptance) may arise—don’t conflate those with pure refusal-to-accept cases.
Timing: missing the three-month minus one day limitation clock from the effective date of termination (EDT).

Mini case study (illustrative)

EXAMPLE: rota change from 4–10pm to 3–9pm

• The employer proposes moving most warehouse staff from 4:00–10:00pm to 3:00–9:00pm. About 10 of 20 need to agree for the business plan to work. That headcount is relevant context, but it’s not the legal test.

• Worker A is a single mum. An earlier finish means she can’t collect from nursery or manage handover arrangements with her ex. That is a predictable childcare constraint that can support an indirect sex discrimination angle and weighs on the Catamaran balance against dismissal.

• Worker B says the earlier shift means heavier boxes at that time of day and he cannot safely lift due to a health issue. He doesn’t need to meet the legal definition of disability under s.6 EqA 2010 for the employer still to have health and safety duties; they should risk-assess, seek Occupational Health, and consider adjustments (different tasks/equipment/assistance) before talking dismissal.

• If the employer imposes the change without sharing evidence, skips consultation, ignores alternatives (e.g., 30-minute tweak; swaps; redistributing heavy-lift tasks; different duties), and doesn’t get OH input for Worker B—then treats both refusals as SOSR or jumps to fire-and-rehire—a tribunal could find the dismissals unfair. Why? Because a less drastic, safer route was available and the overall process wasn’t reasonable under s.98(4) and the 2024 Code.

Short FAQ

Do I have to prove the change wasn’t needed?No. The test is whether dismissal was a reasonable response in the circumstances, not whether the change was strictly “necessary.”

If I keep working, do I lose my claim?No. You can continue under protest while gathering evidence and proposing alternatives.