If you sponsor workers under the Skilled Worker route, the Immigration Salary List (ISL) can look like an easy win: lower salary threshold, lower visa fee, faster hiring decisions. In reality, it’s one of the areas where employers most often trip up — not because the rules are impossible, but because the “80% discount” is frequently misunderstood (and sometimes applied in the wrong place).
This guide breaks down how it works in practice, what you must still pay, and the common mistakes that trigger refusals, compliance action, or (worst case) sponsor licence problems.
What the Immigration Salary List actually does (and doesn’t do)
The ISL is a published list of eligible occupations that can be sponsored on a discounted minimum salary, compared with the route’s “usual” minimum. If the role is on the list, the minimum salary is 80% of the route’s usual minimum rate for Skilled Worker or Health and Care Worker.
Here’s the key point most employers miss:
- The discount applies to the route minimum (the general threshold)…
- …but you still have to meet the going rate rules for the occupation, where applicable.
In plain English: the ISL doesn’t give you permission to “pay 20% less than market.” It gives you a lower entry threshold — but the role still needs to be paid properly for the SOC code and working pattern.
If you’re still at the stage of setting up sponsorship, start with the Sponsor licence application process so your HR systems and right-to-work processes are tight from day 1.
How the “80% salary discount” works in real numbers
The government position is straightforward: if your job is on the ISL, the minimum salary is set at 80% of the usual minimum rate.
In practice, that’s why you’ll often see the ISL minimum stated as £33,400 — because that figure reflects the discounted route threshold.
The pro-rating rule that catches people out
ISL salaries are based on a 37.5-hour week, and must be pro-rated if the worker’s weekly hours are different.
So if you’re hiring part-time, you can’t just say “the minimum is £33,400” and move on. You need to check:
- the worker’s contracted weekly hours, and
- the implied hourly rate, and
- whether the pro-rated annual figure still meets the relevant thresholds.
If you want your sponsorship set-up to survive scrutiny, build your checks into your day-to-day processes — that’s exactly what Sponsor licence compliance is for.
The biggest misunderstanding: “80% of what?”
A lot of refusals come from applying the 80% discount to the wrong benchmark.
Mistake 1: Discounting the going rate instead of the route minimum
Employers often assume ISL means “80% of the going rate.” But official guidance emphasises you must still be paid at least the standard going rate for the job.
Practical takeaway: you don’t get to shave 20% off the going rate just because the job is on ISL. The ISL mainly reduces the general salary threshold hurdle — it doesn’t wipe away the going rate requirement.
Mistake 2: Using the wrong SOC code to “make” the salary work
The SOC code choice is not a creative writing exercise. If you force a role into a code that’s on ISL (or has a lower going rate) when the duties don’t match, you’re handing UK Visas and Immigration a reason to refuse the visa and question your sponsor compliance.
If you’re sponsoring workers already, keep an eye on changes that trigger reporting and scrutiny — Business changes that trigger sponsor reporting is a useful reminder of how quickly things can unravel after a restructure, merger, or role change.
Where employers get caught out (the “pain points” list)
Below are the issues we see repeatedly with ISL salaries and Skilled Worker sponsorship generally.
1) Pro-rating done incorrectly
This is the classic one. Salary looks fine annually, but the contracted hours mean the hourly rate (or pro-rated threshold) doesn’t actually meet the rules. ISL salaries are explicitly tied to a 37.5-hour week baseline.
2) Non-guaranteed pay counted as salary
Bonuses, commission, overtime, and discretionary allowances are often treated as if they’re guaranteed base pay. That can blow up an application if the caseworker only accepts guaranteed elements.
A safer approach is to structure compensation so your guaranteed pay clears the relevant thresholds without needing “extras.”
3) Salary sacrifice and deductions reducing the effective pay
If the worker’s contractual gross pay meets the number, but salary sacrifice arrangements bring it down in a way that matters for immigration purposes, you can end up with a compliance gap.
4) “It’s on ISL so we’re fine” — but the going rate is higher
This is the most expensive misunderstanding. You meet £33,400, but the going rate for the SOC code (and your hours pattern) means you should be paying more. Official guidance makes clear the going rate still matters.
5) Certificates of Sponsorship details don’t match the contract
If the CoS says 37.5 hours but the contract says 40 (or vice versa), or salary figures don’t align exactly, you can expect questions.
If you want a clean overview of how the route works end-to-end, revisit the Skilled Worker visa guide and make sure your CoS and contract are built from the same numbers.
6) Role “drift” after sponsorship
The worker starts in an eligible ISL role, but the duties shift over time — and no one spots that the SOC code no longer fits. That’s a genuine compliance risk, especially during a Home Office visit.
If you’re worried about what happens when the Home Office loses confidence, read Sponsor licence suspension and revocation so you understand the stakes and the usual triggers.
ISL vs other salary discounts: don’t mix them up
ISL is only one of several “paid less” concepts in the system. There are also discounts in other contexts (for example, certain PhD-related discounts).
If you’re using sponsorship in a more complex business plan (including founders hiring themselves through a UK company), be especially careful about salary structure and documentation.
And if your organisation is exploring alternative sponsored routes for overseas entities, it’s worth comparing with:
A simple employer checklist before you rely on the ISL discount
Before you build a recruitment plan around ISL salaries, pressure-test the numbers:
- Confirm the role genuinely matches the SOC code (duties first, then the code).
- Check whether the role is actually on the ISL (and that you’re using the current list).
- Calculate salary using the worker’s real weekly hours (pro-rate properly).
- Ensure guaranteed pay meets:
- the ISL minimum route threshold, and
- the occupation’s going rate requirements (don’t assume 80% applies there).
- Make sure CoS, contract, and payroll all match.
If you want to support putting this into a repeatable HR process (and not a one-off scramble per hire), the Sponsor licence applications service page is a good starting point, because it focuses on getting your systems “inspection-ready”, not just getting the licence granted.
Need help checking an ISL salary before you assign a CoS?
If you’re about to sponsor someone using the ISL discount and want to avoid a refusal (or a future compliance headache), it’s worth getting the salary, SOC code, and CoS details checked before you press submit.
You can also review the firm’s scope of support on Services & fees and then decide whether you need a one-off sense check or full sponsorship support.
Ready to move forward with your UK immigration plans? Garth Coates Solicitors can guide you at every step — from eligibility checks and document preparation to submission and follow-up. If you’re launching a business, our uk start up visa team can help you build a strong application. Need support with work routes? Speak to a trusted skilled worker visa solicitor today. We also advise on the uk self sponsorship visa for entrepreneurs seeking more control. Studying in the UK? Our student visa solicitors are here to help — contact us now for tailored advice.
