Many stories about the Nissan deal are circulating, but it looks as if Nissan have been promised tariff free access to European markets. It's unclear whether other companies will get this, and as Keir Starmer pointed out, Nissan now know more about this than MPs or voters! Commercial secrecy is one thing, but this is becoming ridiculous. Brexit means Brexit, but what that means is not for you to know.
I guess, reading between the lines, May is worried about softening Brexit, and the reaction of the hard mob.