The market has second thoughts
There are some second thoughts going through the cable market at the moment as it rebounds to 1.3561 from as low as 1.3488 as May was speaking.
There was a report she would threaten to leave the EU early and that would have been GBP-negative. But it was a ridiculous report to begin with (even if it was from a credible source).
The news here is that May wants to stay for another two years, which will probably turn into another 10 years. Every day it's a slow shift towards remaining after all.
I really don't see any reason to sell GBP in the speech.