the appellant was, at one time, entitled to impeach the judgment
on that ground. So any party isentitled to impeach a judgment
of an inferior Court by way of prohibition if it exceeds its juris-
diction. But this right may be lost. In the case of the Mayor
of London vy. Cox, which embodies the whole law of prohibition,
the rule was stated by Mr. Justice Willes as follows QQ2): -
" Where, however, the defect is not apparent, and depends upon
some fact in the knowledge of the applicant which he had an
opportunity of bringing forward in the Court below, and he has
thought proper, without excuse, to allow that Court to proceed to
judgment without setting up the objection, and without moving
fora prohibition in the first instance, although it should seem that
the jurisdiction to grant a prohibition in respect of the right of
the Crown is not taken away, for mere acquiescence does not give
Jurisdiction, yet, considering the conduct of the applicant, the
importance of making an end of litigation, and that the writ,
though of right, is not of course, the Court would decline to inter-
pose, except perhaps upon an irresistible case, and an excuse for
the delay, such as disability, malpractice, or matter newly come to