"In designing our rulebook we want to be as transparent as possible and to set out to the industry the fundamental principles that underpin the rulebook and what we expect of firms," Sasha Mills, BoE executive director for market infrastructure, told a conference held by ISDA, a global derivatives industry body.

"Therefore, we are exploring proposing 'fundamental rules' that would underpin the whole regime and so help firms anticipate how we will assess their compliance with more specific rules."

(Reporting by Huw Jones; Editing by Andrew Cawthorne)