Many in Brussels today will no doubt still be confused as to the reasoning of leaving Erasmus, especially given its place as the jewel in the EUs crown when it comes to cross-continental cooperation. And there is certainly no doubt that Erasmus, which celebrated its 30th anniversary in 2017, is something for the EU to be proud of. But for the UK leaving it was as much about the financial aspects of the project as it was the political ones.
https://www.neweurope.eu/article/erasmus-and-brexit/