Treasury source said Raab was shown letter ahead of publication (via @TomBoadle) & it was agreed that it would be published alongside the impact studies
The *actual* content of the letter has no new forecasts but if does offer new language impressing on colleagues the benefits over the Chequers deal (which many hate) over No Deal 
For many Brexiteers, No Deal is better than a Chequers Deal (TM @ShonaSomerville) and so Remainer-in-chief Hammond’s reminder of the ec threat of no deal sparked anger even though he’s actually endorsing No 10’s position
But there is an element of ‘tin-ear’ Hammond in releasing the letter on same day as the No Deal impact studies. No 10 had been desperately trying to avoid accusations of peddling Project Fear 2.0 from Brexiteers. In that context Hammond timing v unhelpful
Amid all the focus on the timing Hammond’s ‘hand-grenade’ No Deal letter, here’s a handy @skynews summary of those 25 impact studies released yesterday. No deal better than a Chequers deal? Brexiteers I spoke to yesterday still say yes.
