Tone of compromise still leaves battles brewing

Theresa May offered a respectful farewell to Donald Tusk rather than bold threats

It's arrived. The letter has been handed over, so the process of our leaving the European Union is underway.

The prime minister described it as a "moment of celebration for some, disappointment for others", acknowledging for one of the first times the 48% who wanted to stay in the EU.

But rather than a breezy goodbye, the tone of Mrs May's letter was instead a respectful farewell.

It was a marked, and probably inevitable, change from her conference speech at the Tory get-together in October, and a sentiment more conciliatory even than her Lancaster House speech in January that set out her main priorities, and admitted, once and for all, that the UK would not stay in the single market.

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There is no repetition from that speech of the prime minister's bold threat to walk away if a deal couldn't be done, where she said starkly, "no deal is better than a bad deal". That threat went down very badly with EU diplomats, even though as a negotiating position it perhaps had to be said. But it's notable that it was nowhere to be found in today's letter or today's statement, and that the PM made plain in fact how much she wants to work to avoid that happening.

It's a far cry from the foreign secretary claiming it would be "perfectly ok" for us to walk away with no conclusions.

There were notable lines that may be seen as concessions by some too; a hope for early agreement on "phased implementations", respectful promises of staying the EU's "closest friend and neighbour", no mention of the desire to control immigration, and a promise that "significant powers" will go to Holyrood, Cardiff and Stormont, as they return from Brussels.

But woven through the letter is the UK's desire referenced on several occasions; to talk about the future deal at the same time as settling the terms of our departure.

That is not the EU's preferred position and an early defeat, or early victory, on the timetabling of the talks for the UK could make all the difference. This debate has the snappy title of parallelism versus sequentialism as I've written before.

So despite today's tone of compromise, there are plenty of battles brewing.