Theresa May’s March 29, 2017 letter to Donald Tusk notified intentions to withdraw from two named bodies: the European Union and the European Atomic Energy Community, or Euratom. The letter addressed both notifications to the European Council. Reading it only as a statement about EU membership misses the second expressly named object. [LETTERBODY]

For the EU notification, May cited Article 50(2) of the Treaty on European Union. For Euratom, she cited that same provision as applied by Article 106a of the treaty establishing the European Atomic Energy Community. Those are the references the letter used; this account does not interpret their legal operation. The document records intentions to withdraw, not completed departures. [LETTERBODY]

A different object appeared in May’s Commons statement that day. She promised votes in both Houses of Parliament on an agreed final UK–EU deal before it took effect. That prospective agreement was not the notification letter. The promise supplies context for the distinction between notifying withdrawal intentions and putting a negotiated deal to Parliament; it does not establish a vote held or a deal reached. [COMMONS][LETTERBODY]

This retrospective uses current official representations retrieved in October 2026, not verified 2017 snapshots. Exact historical wording and cutoff availability remain unconfirmed. Both records come from the same interested government, not independent corroborating sources. [LETTERBODY][COMMONS]

Source documents

  1. Prime Minister's Commons statement on triggering Article 50https://www.gov.uk/government/speeches/prime-ministers-commons-statement-on-triggering-article-50
  2. Prime Minister’s letter to Donald Tusk triggering Article 50https://www.gov.uk/government/publications/prime-ministers-letter-to-donald-tusk-triggering-article-50/prime-ministers-letter-to-donald-tusk-triggering-article-50