IR35 Insurance for Contractors: What It Covers, What It Costs, and Whether You Need It

Bottom line: IR35 insurance does not pay your tax bill if HMRC determines you were inside IR35. It pays the legal and accountancy costs of defending your outside-IR35 status during an investigation — which can run to £15,000–£50,000 without cover. For any contractor operating outside IR35, this insurance is close to essential.

What IR35 insurance actually covers

This is the most misunderstood point about IR35 insurance: it does not pay the tax, NICs, and penalties HMRC would charge if you lost an IR35 determination. Those costs are yours. What IR35 insurance covers is the professional fees incurred while defending your status during the investigation process — which is a separate, significant cost.

A typical IR35 enquiry involving a specialist tax investigation firm and barrister representation can cost:

• £3,000–£8,000 for a simple compliance check or informal enquiry
• £10,000–£25,000 for a formal HMRC enquiry with correspondence and negotiations
• £25,000–£50,000+ if the case proceeds to a Tax Tribunal

IR35 insurance covers these professional representation costs up to a specified limit — typically £50,000–£100,000 depending on the policy. The insurer also provides access to their legal team from the moment the enquiry begins.

What IR35 insurance does not cover

• The unpaid tax, National Insurance contributions, and interest if HMRC wins the determination
• Penalties for deliberate non-compliance
• Tax investigations on issues unrelated to IR35 (you need separate Tax Investigation cover for that)
• Enquiries into periods before your policy start date (in most policies)

Why "I'm outside IR35" is not enough protection on its own

HMRC can open an IR35 enquiry on any contractor engagement at any point within six years of the relevant tax year — and in cases of suspected fraud, even further back. An outside-IR35 status determination at the start of a contract does not preclude investigation. HMRC has made clear it will continue targeting disguised employment across the contracting sector.

The investigation process is stressful, time-consuming, and expensive regardless of whether you win. IR35 insurance doesn't reduce your risk of investigation — it removes the financial barrier to defending yourself properly when it happens.

IR35 insurance vs Professional Indemnity insurance

These are two separate products that contractors often confuse or conflate. You typically need both.

Professional Indemnity also plays a secondary IR35 role: holding and maintaining PI insurance is one of the indicators HMRC uses to assess whether a contractor operates as a genuine independent business. Contractors without PI in a role where it's professionally expected are marginally more vulnerable to an inside determination.

How much does IR35 insurance cost?

Premiums depend on your contract rate, contract duration, and the level of cover you choose. As a guide:

Higher contract values typically attract higher premiums. Both providers offer combined policies that bundle IR35 cover with other contractor insurance products. For a detailed head-to-head comparison see our Qdos vs Kingsbridge comparison.

When to buy — and when cover starts

Buy IR35 insurance before your next contract starts, not after an enquiry opens. Most policies do not cover investigations relating to periods before the policy start date. If you're already mid-contract without insurance, buy it immediately — coverage starts from the policy date forward.

Annual renewal is standard. Review your cover level at each renewal — if your contract rate has increased significantly, the cover limit should increase proportionately.