Britain is no longer Europe's "center of gravity" in the eyes of America -- and particularly if Joe Biden is elected president next month -- according to former senior diplomat and cross-bench peer Peter Ricketts.

After 40 years defending Britain's interests in the world, Ricketts offered a sobering interpretation of the impact Brexit is having on the U.K.'s international standing.

"When Biden looks towards Europe, he will see Paris and Berlin more as the center of gravity of what's really important for America in Europe, both economically and in security terms, and Britain will be seen rather as an outlier, rather outside the mainstream of Europe," he said.

"There will continue to be an important bilateral relationship on defense and security of course, but in other areas, Britain will not have the same prominence it has been used to having in Washington because, frankly, Britain is less useful to the U.S. administration."