U.S. Treasury Secretary optimistic on trade deal with UK

Speaking at an event held at the Chatham House think tank in London, Mnuchin said he had a breakfast meeting with British finance minister Sajid Javid earlier on Saturday, having also spoken to him this week at the World Economic Forum in Davos.

"We're focused on trying to get this done this year because we think it's important to both of us," he told the audience.

While he conceded that Britain may need to finalize some issues with the European Union before it could discuss them with Washington, he didn't see this as creating a delay.