Inward Processing Relief (IPR) in the UK – how to suspend duty on imported components

Inward Processing Relief (IPR) is one of the most powerful customs cost-optimisation tools available to manufacturers and processing companies in the United Kingdom. The mechanism is straightforward, though operationally demanding: you import raw materials or components into the UK without paying customs duty — on the condition that they are processed, transformed, or incorporated in a manufacturing process, and that the finished product is then re-exported outside the UK. Duty is suspended, not remitted — if the finished goods do not leave the UK within the prescribed period, the customs debt becomes payable. For Polish exporters working with UK manufacturers, understanding IPR in the UK is essential: it determines whether your components enter the UK at 0% duty and whether the entire supply chain is cost-efficient. This article explains how IPR works in the UK after Brexit, how to obtain HMRC authorisation, and what operational obligations the procedure entails.

What is IPR and how does the duty suspension mechanism work

IPR (Inward Processing Relief) is a customs procedure set out in the UK Customs and Excise Management Act and detailed HMRC regulations. Its mechanism is based on the principle of suspension, not exemption from duty.

How it works:

Import of components (0% duty — suspended)
        ↓
Processing / manufacturing in the UK (added value)
        ↓
Re-export of finished product outside the UK
        ↓
Customs debt extinguished — duty never paid

If part of the production remains on the UK market (so-called uncleared goods), duty must be paid proportionally on that portion.

Key terms: - Period of discharge: The time within which goods must leave the UK or the customs debt must be settled. In the UK this is typically 6 months, with extension to 24 months possible with HMRC approval. - Bill of discharge: A reconciliation document submitted at the end of the period — it shows how much raw material entered, how much was processed and re-exported, and how much, if any, remained in the UK. - Yield rate: The ratio of finished product to raw material — critical for correct settlement (e.g. "1,000 kg of steel yields 850 kg of finished parts").

Who can use IPR in the UK — eligibility requirements

IPR is not a procedure open to every importer. HMRC sets specific requirements:

Entity requirements: - Company registered in the UK (or a UK EORI for overseas entities with a fiscal representative) - Ability to maintain customs records as required by HMRC - Good customs compliance history (no serious customs violations) - Financial standing — HMRC may require a Customs Comprehensive Guarantee covering the potential customs debt

Types of activity qualifying for IPR: - Industrial manufacturers (manufacturing) — the most common case - Repair and maintenance companies - Processing and finishing companies - Companies carrying out product testing, calibration, or certification

Overseas entities (Polish companies): A Polish company can, in principle, obtain a UK IP authorisation, but this requires a UK EORI and, in practice, the appointment of a tax representative or a registered UK branch. In reality, IPR in the UK is used primarily by UK-established companies or their subsidiaries.

How to apply for IP authorisation — HMRC procedure

Form: C&E 1154 (application for authorisation of special procedures, including IP) — available on gov.uk and submitted electronically via CHIEF or CDS.

Information required in the application: - Description of the goods to be imported (CN/HS codes, textual description) - Description of the processing operation (manufacturing process) - Description of the finished product after processing - Estimated volumes (quantities per year) - Yield rate — e.g. "1,000 kg of steel yields 850 kg of finished parts" - UK port of entry and place of processing - Intended period — typically an application for 3 years with an option to renew

Processing time: HMRC typically issues a decision within 30 working days (approximately 6 weeks) of receiving a complete application. For complex cases, up to 3 months.

Cost of authorisation: There is no official fee for submitting the application. The costs borne by the company are: time spent preparing the documentation and, where required, a customs guarantee (the cost of which depends on the bank or insurer and the amount of the potential customs debt).

Equivalent Goods — operational flexibility in IPR

One of the important features of the UK IP regime is the ability to use equivalent goods.

What this means: Instead of processing the exact same raw material you imported, you may use equivalent raw materials available in the UK — provided they have an identical technical specification (same CN code, quality, and properties).

Practical example: You import grade 316L stainless steel from Poland for a UK precision manufacturer. The UK manufacturer holds grade 316L steel in stock from a local distributor with identical parameters. Under the equivalent goods provisions, the manufacturer can use the locally sourced steel in production and re-export the finished parts — while your batch of steel from Poland "covers" the IPR customs debt. This gives flexibility in inventory management without physically segregating raw materials.

Equivalent goods — limitations: HMRC must grant approval for the use of equivalent goods in the authorisation. Not all products and processes qualify.

Bill of Discharge — settling the IPR procedure

The Bill of Discharge (BoD) is the key settlement document for IPR, submitted to HMRC at the end of the processing period or quarterly (if the authorisation provides for this).

What the Bill of Discharge must contain:

Element	Description
Quantity of goods imported	Volume of raw material per import declarations
Quantity processed	Volume used in production
Yield rate	% of raw material converted into finished product
Quantity re-exported	Volume of finished goods that have left the UK
Quantity remaining in UK	If non-zero — the basis for calculating duty payable
Export MRN references	References to export declarations confirming re-export

Submission deadline: HMRC typically requires the BoD to be submitted within 30 days of the end of the processing period.

Risk of failing to submit the BoD: Failure to settle the account results in full duty being levied on all imports, plus interest and potential administrative penalties.

Example — a Polish company exports to a UK manufacturer

A practical scenario illustrating how IPR works from the perspective of a Polish exporter and its UK customer:

Situation: Polish company Technomet Sp. z o.o. exports aluminium castings (HS 7601.20) to UK automotive component manufacturer BritoCast Ltd of Birmingham.

Without IPR: - BritoCast imports castings from Poland into the UK → pays 5% duty (MFN; for simplicity, ignoring TCA preferential origin rules) - BritoCast processes the castings → finished automotive components - BritoCast exports to a customer in Germany - BritoCast recovers the duty through a drawback procedure — but this requires a separate application and is less efficient

With IPR: - BritoCast holds an IP authorisation from HMRC for importing aluminium castings - Import from Poland → 0% duty (suspended) - Processing → automotive components - Export to Germany → BoD confirming 100% re-export → customs debt extinguished - BritoCast saves duty across the entire import

Benefit for Technomet (PL): BritoCast can offer a better price or increase order volumes, because IPR eliminates their customs cost. Polish raw materials become more price-competitive against suppliers from third countries.

IPR versus other customs procedures — when to use which

Procedure	When to use	Main advantage
IPR (Inward Processing)	Import of raw materials for processing and re-export	Duty suspension — no cash-flow impact from duty
End-Use Relief	Import for a specific, defined end use (e.g. ship repair)	Reduced duty rate for a specific purpose
Customs Warehouse	Storage of goods without processing	Defers the decision on the destination of goods
Temporary Admission	Temporary import without processing (exhibitions, testing)	No duty or VAT when goods are returned
Drawback	Duty repayment after re-export — standard import route	Available without authorisation, but less efficient

IPR vs Customs Warehouse: A customs warehouse stores goods; IPR allows them to be processed. If your operation involves manufacturing, IPR is the right tool. The two can be combined: goods first placed in a customs warehouse, then moved into the IP procedure.

IPR vs End-Use Relief: End-Use Relief requires a defined end use for the goods and provides a fixed reduced rate, but not zero. IPR gives zero duty, but requires re-export. If goods remain in the UK after processing, End-Use Relief may be the better option.

Risks and compliance — what can go wrong

IPR requires rigorous record-keeping. The most common issues are:

1. Absence of re-export documentation: HMRC requires evidence that goods left the UK — the MRN of the export declaration, transport documents. If export documents are incomplete, HMRC will levy duty.
2. Exceeding the processing period: If goods are not processed and re-exported within the prescribed time, a customs debt arises automatically on the full import.
3. Incorrect yield rate: If the actual yield rate differs significantly from the declared rate, HMRC may challenge the BoD.
4. Operating without authorisation: Using the IP procedure without HMRC authorisation is a customs law violation — administrative penalties and possible revocation of EORI.