Worth reading in full
1. But reason DUP are worried is it implies May is poised to accept an arrangement that would tie NI more closely to the EU than GB - backed up by Cabinet source who told me No 10 solution inc arrangement like 'customs partnership' for GB and 'customs union' for NI
2. This is NOT what No 10 is saying right now - they say PM would never accept arrangements that hive off NI and negotiations still ongoing
3. But the letter raises the possibility of 'specific alignment solutions' for NI - so potentially different regimes on the two sides of the Irish Sea - that's why DUP are so cross - remember PM needs their votes desperately
4. If it's enrage the DUP or lose the chance of the withdrawal deal - what does the PM do? Recent conversations with senior sources suggest it might be the former - (and increasing checks have been on table for ages) but high, high stakes
