Analysis: Brexit letter brings change of tone from PM

It is in tone as much as substance that makes the document interesting reading.

Gone are the veiled threats made in the Prime Minister’s Lancaster House speech in Janiary suggesting the failure to secure single market access would leave this country “free to change the basis of Britain’s economic model” - widely considered a euphimism for low tax, low red tape and possibly low wage, economy sucking investment away from the continent.

Instead, there are words of concession and conciliation.

Mrs May acknowledges that Britain will lose its voice in the shaping of EU trade rules. So much for Foreign Secretary Boris Johnson’s assertion that the UK can have its cake and eat it.

And the staunchest Eurosceptics will have choked at her repeated references to the “deep and special partnership” between the UK and the continent.

Much will be made of the letter’s focus on security issues and what could be read as a threat to withdraw co-operation if agreement in other areas cannot be achieved.

But as someone who was Home Secretary for six years it is almost impossible to imagine that even the complete collapse of trade talks would lead the Prime Minister to pursue a course carrying grave risks for the UK as well as Europe.