Boddington v BTP [1998]

both principle that procedural exclusivity does not apply where private rights
involved and collateral attack
of Lords held it was open to defendant in criminal proceedings to challenge
byelaw, or administrative decision made thereunder, where prosecution was
premised on its validity, unless clear Parliament intent to contrary.
to measure did not have to rely on JR.
exclusivity would only be insisted upon where sole object of action was to
challenge public law act or decision.
not apply in:

Civil case where individual sought to establish private law rights which could
not be determined without examining validity of public law decision, nor

Civil case where defendant sought to defend himself by challenging validity of
public law decision, nor

Criminal case where liberty of subject at stake.