(4) The following persons may intervene
and be heard in proceedings to which they are not already parties--
(a) the
Attorney General,
(b) a Minister who administers the legislation that confers
or imposes functions the exercise (or purported exercise) of which are in
issue in the proceedings,
(5) A Minister may (from money otherwise lawfully available for the purpose)
authorise the payment to a party to the proceedings in which the Minister or
the Minister's delegate intervenes such costs (if any) as the Minister
considers were reasonably incurred by that party in relation to the
proceedings as a result of that intervention.