12th June 2026
National Insurance (NI) behaves like a “stealth” tax in practice. It raises revenue from earnings, is visible as a payroll deduction, and increasingly functions like a second income tax rather than a narrowly hypothecated social‑insurance contribution.
Purpose vs reality
NI is presented as funding the State Pension and some benefits, but receipts flow into general government revenue and are used alongside income tax.
How it’s charged
NI is calculated on earnings per pay period and uses different thresholds and rates to income tax, so its effects differ from income tax.
Recent policy moves
Changes to thresholds and employer rates have shifted who pays and how much — making NI a more significant cost for some households and employers.
Why people call NI a “stealth” tax
It functions like a second income tax. For many employees the combined marginal rate (income tax + NI) is what matters — NI increases take-home pay down just as a rate rise would.
Policy changes can raise revenue quietly. Raising employer NI, lowering thresholds, or freezing uprating increases receipts without headline income‑tax rate changes.
Complexity hides the scale. Different thresholds, classes, and per‑pay‑period calculations make NI less intuitive than income tax, so public attention is lower even when the burden rises.
Risks, trade‑offs and what to watch (practical)
Risk: Treating NI as a stealth revenue source can erode trust if people feel contributions no longer buy the promised benefits.
Economic trade‑off: Higher NI (employee or employer) raises labour costs and can affect hiring, take‑home pay, and wage negotiations.
Distributional effect: NI hits earned income only, so people with large non‑earned income (dividends, rental) can face lower effective NI burdens.
Practical steps for individuals
Check your pay slip and thresholds to see how NI affects marginal rates.
Use tax‑efficient saving (pensions, ISAs) to reduce taxable earnings where appropriate.