"Some period of adjustment would be good," Jay Clayton told the business daily in an interview, extracts of which were published online.

"The intricacies of our financial system are significant and it's difficult to identify all the ways in which a decree that something is no longer valid may impact."

British ministers met Tuesday to intensify plans for leaving the European Union without a deal -- a prospect that is becoming more likely as Prime Minister Theresa May plays for time with just 101 days to go until Brexit.

Speaking of a possible no-deal, Clayton told the FT: "If you asked me that nine months ago, I would have said, boy it would surprise me.

"If you're asking me today... let me put it this way, I think it's prudent for me to spend time thinking about what that means."

The newspaper added that Clayton planned to increase the number of SEC workers focused only on Brexit.