Twenty-five banks are “well advanced” in their talks with the European Central Bank to retain a foothold in the European Union even after Britain leaves the bloc, the ECB’s top supervisor Daniele Nouy said on Monday.

Banks that conduct their EU business out of London are having to secure a new or expanded banking licence from the ECB if they are to keep unfettered access to the 27-countries club after Brexit.

“We have 25 banks... which possibly are very well advanced” she told a conference, adding that the tally would rise to 37 if other financial entities such as investment firms are included.

Nouy said the ECB had talks with 50-60 firms in total.

Britain is due to formally leave the EU in March 2019.