The UK has chosen Peppol. Here’s what that means for your AP function.

For the past seven months, finance teams preparing for the UK’s 2029 e-invoicing mandate have been working with one significant unknown: which network would the mandate actually run on?

On 23 June 2026, that question was answered.

As part of HMRC’s Tax Update 2026: Simplification, Modernisation and Fairness policy paper, the government confirmed that Peppol will be the core interoperability network for e-invoicing in the UK. The mandate itself — mandatory structured e-invoicing for all VAT invoices in B2B and B2G transactions — remains on course for 1 April 2029. A full implementation roadmap, including technical standards and phasing detail, is expected at Budget 2026 in November.

This is the most significant development in the UK’s e-invoicing programme since the mandate was announced at Autumn Budget 2025. It is also, for finance and AP leaders who have been waiting for certainty before committing to preparation, the clearest signal yet that waiting is no longer a viable posture.

What Peppol actually means in practice

Peppol is not new technology. It is a globally adopted, open network that allows organisations to exchange structured electronic invoices directly between financial systems, without manual handling, re-keying, or format translation. It operates across more than 90 countries. In the UK, it has been in use in the public sector since 2019, when NHS Supply Chain required its suppliers to issue e-invoices through the Peppol network.

The model the UK is adopting is a decentralised four-corner model. Suppliers and buyers exchange structured invoices through their chosen software providers or accredited Peppol Access Points. HMRC does not receive invoice data in real time as part of the initial mandate. This is a deliberate design choice which distinguishes the UK approach from the clearance-model systems used in Italy and France, where invoices must pass through a government platform before reaching the recipient.

The immediate practical implication is straightforward: if your AP or ERP platform cannot connect to the Peppol network, it will not be compliant from April 2029. That is the question to be asking your software provider right now.

As Sovos, which is actively engaged with HMRC in the co-design of the UK framework, noted following the announcement, businesses selecting a provider should look beyond Peppol connectivity alone and consider partners with proven tax reporting expertise because HMRC has signalled the four-corner model could evolve into a five-corner model involving digital reporting at a later phase.

What is still to be confirmed

The Peppol confirmation resolves the network question. It does not resolve everything.

The specific document standard for the UK mandate is still being developed. The strong expectation, based on the work of the OpenPeppol UK Working Group established in late 2025, is that the UK will adopt PINT UK, a localised version of the Peppol International Invoice standard built on the EN 16931 semantic model. This preserves the core European standard while embedding UK-specific VAT rules, and maintains cross-border interoperability for UK businesses trading with European partners. But PINT UK has not yet been formally mandated.

Several other design elements remain open ahead of Budget 2026:

• The specific technical specifications and mandatory data fields
• The accreditation requirements for Peppol Access Points
• The transitional arrangements for businesses running legacy EDI systems or proprietary invoicing platforms that predate Peppol
• Whether the mandate will be phased, with larger businesses going first in April 2029 and smaller taxpayers following in April 2030

HMRC has explicitly acknowledged the legacy system challenge, confirming it will continue engaging with stakeholders on how organisations that cannot interoperate with the future network will be supported. That is a meaningful acknowledgement of the real-world complexity involved but it should not be read as an indication that waiting is safe. The direction is confirmed. The question is only about transitional arrangements for those who need more time to get there.

The window is shorter than it looks

April 2029 is 33 months away. In calendar terms, that feels manageable. In implementation terms, it is not as comfortable as it appears.

E-invoicing readiness is not a technology problem alone. As we covered in our piece on seven realities from an implementation consultant, the technical connectivity is typically the fastest part of the process. What takes time is everything around it: master data quality, supplier onboarding and education, ERP alignment, exception workflow design, and cross-functional co-ordination between finance, IT, and procurement.

Organisations with large or complex supplier bases face an additional constraint. Getting suppliers onto a new invoicing network, especially suppliers who have been sending PDFs by email for years, requires communication, testing, and in some cases significant change management. That work does not compress into a few weeks.

There is also a timeline pressure that is independent of the UK mandate entirely. Trading partners in Belgium (mandatory since January 2026), Germany, and France already require UK suppliers to send structured invoices in some contexts. For any UK finance team with significant cross-border transaction volumes, Peppol readiness is not a 2028 conversation, but a now conversation.

What to do before Budget 2026

The November roadmap will bring the technical standards needed to move from planning to execution. Between now and then, there is meaningful preparation work that does not require those standards to be finalised.

Start with an honest assessment of your current state. How are invoices currently created, received, and processed? Where does manual handling still sit in the workflow? Which ERP systems and entities are in scope? The answers to these questions will shape your implementation timeline regardless of which specific Peppol format the UK mandates.

Talk to your ERP and AP software provider. Peppol connectivity is now confirmed as the requirement. There is no reason for providers to delay product development, and no reason for you to delay asking for their roadmap and timelines.

Audit your supplier master data. As we have seen across e-invoicing implementations in other jurisdictions, data quality is the single most common cause of implementation problems. Missing VAT IDs, incorrect legal entity names, and inactive or duplicate supplier records do not become visible until invoices start failing validation. Finding them now is considerably less disruptive than finding them after go-live.

The UK’s e-invoicing journey has moved from announcement to network confirmation in seven months. The November Budget will move it from network confirmation to full roadmap. If you are still at the stage of monitoring rather than preparing, the next milestone is likely to be the one that makes the 2029 date feel very close indeed.

For a fuller picture of what e-invoicing implementation actually involves, see our UK e-invoicing mandate guide and our e-invoicing readiness checklist.

Not sure how prepared your organisation is? Start with a readiness assessment.