A top US regulator has threatened to prevent European banks from accessing US futures markets over EU plans for the oversight of foreign clearing houses after Brexit.

Speaking at the Futures and Options Expo in Chicago, Christopher Giancarlo, head of the Commodity Futures Trading Commission, called the EU plans to amend European Market Infrastructure Regulation “unprecedented and wholly unacceptable” and warned they could create “costly burdensome regulatory requirements” in the US.

Mr Giancarlo said that if the EU did not change the existing plans he would have “no choice” but to select from a wide range of actions that includes barring EU banks from using US financial infrastructure such as the Chicago Mercantile Exchange.

“These are blunt and strong tools”, he said. “We are fully aware of the devastating impact they would have on market access and trading liquidity provision on national markets in which they would be applied.”

Mr Giancarlo added that was keen to negotiate changes to the planned EMIR amendments: “I am ready to jump on even more planes, trains, and automobiles bound for any European capital to work out a sensible approach.”

The tussle for control of a serious chunk of the clearing market has emerged as one of Brexit’s key battlegrounds.