ultra vires
Concise Oxford English Dictionary © 2008 Oxford University Press:
ultra vires /ˌʌltrə ˈvʌɪriːz, ˌʊltrɑː ˈviːreɪz/
▶adjective & adverb Law beyond one's legal power or authority.
– origin L., lit. ‘beyond the powers’.
'ultra vires' also found in these Oxford entries:

