Part VI
Mutual legal assistance in criminal matters
CHAPTER III
Special forms of international assistance
Article 155
Temporary surrender of persons in custody
2. Without prejudice to the provisions of the preceding paragraph, surrender shall be refused if:
a) the presence of the person concerned is necessary at criminal proceedings pending in Portugal;
b) it is liable to prolong the provisional arrest of the person concerned;
c) regarding the circumstances of the case, the Portuguese judicial authority does not deem surrender to be convenient.
EDIT.