  The voting rules of the European Council (EU) under the Treaty of Lisbon
became effective on 1 November 2014. Kurz \& Napel (2015) showed that the
dimension of this voting system is between $7$ and $13,368$. The lower bound
$7$ actually sets a new world record for the dimension of the real-world voting
bodies. In this article, by finding a new way to represent the union of two
weighted games as an intersection of certain weighted games (Theorem 1), we
greatly reduce the upper bound $13,368$ to just $25$. We also consider what
will happen to our upper bound and Kurz \& Napel's lower bound if the United
Kingdom is no longer a member of the European Union Council.
