einvoice-preflight had 27 country pages and no United Kingdom. It now has one.
What the secondary sources read agree on: the government confirmed at Autumn Budget 2025 that e-invoicing goes ahead from April 2029, for VAT invoices in business-to-business and business-to-government sales; Peppol was reported as the network on 23 June 2026; there is no real-time reporting to HMRC in the first phase. What they do not give: phasing by business size, penalties, or a UK profile. The roadmap is due with Budget 2026, which had not happened yet. The page says so and states no penalty amount.
Limits: gov.uk and HMRC were not reachable from this session, so every date is from law-firm, accountancy-body and vendor pages found by search. The checker tests EN 16931 and Peppol BIS Billing 3.0 files, not a UK profile, because none exists yet. The page, the country table and the sitemap carry that caveat.