Here we go, then. Bags packed? Passport up to date? Ready to leave forever? Me neither.

In the next hour the British Ambassador to the EU, Sir Tim Barrow, will officially hand over Theresa May's letter to European Council president Donald Tusk, triggering Article 50 of the Lisbon Treaty.

We're straight into PMQs in the House of Commons, during which we expect Article 50 to be set in motion across in mainland Europe.

The first question sees Ms May assuring Ulster Unionists that Northern Ireland following Brexit will be fully protected. The border between NIR and ROI hardly needs complicating further, which splitting from the EU will almost certainly do.

Angus Robertson, SNP, with a steely question regarding the devolved governments and their (lack of) say in the triggering of Article 50. Her response? "This is a matter for the UK government. Can I remind him that Scotland is part of the United Kingdom."

Robertson moves on to the matter of the Second Scottish Independence Referendum. May: "The SNP consistently talks about IndyRef. Now is not the time to be talking about it. On today, of all days, we should be coming together as a United Kingdom to get the best deal for Britain."

It's 12:20pm. I think that's it, folks. The letter was due to be delivered to Tusk at this moment. Meanwhile PMQs rattles along.

We're expecting to see a photo of the letter being handed over at some point. Meanwhile, Theresa May will address the House of Commons once PMQs is done (in about 5 minutes or so).