The new trade deal means big changes for Britain's lucrative financial services industry. The sector no longer has blanket access to Europe's single market.
Instead it has to rely on Brussels granting approval to maintain its ties with the continent.
Emma Reynolds is Managing Director of Public Affairs, Policy and Research at TheCityUK, an industry body that represents Britain's financial sector. She says most businesses have had time to prepare for the change:
"We lose the right to passporting [but] our member firms already knew that this was coming so have have already set up subsidiaries in other financial centres around the EU and have moved assets and staff prior to today."
To listen to the full interview with Emma Reynolds, click on the media player above.