Tortoise, I think that's the rules for civil trials, here are the rules for criminal hearings. They're not as broad for reasons to have hearings held in private.
_________________
2. Hearings from which the public may be excluded
2.1 Trials in private: all criminal courts**
In accordance with the open justice principle, the general rule is that all court proceedings must be
held in open court to which the public and the media have access. The common law attaches a very
high degree of importance to the hearing of cases in open court and under Article 6 ECHR the right
to a public hearing and to public pronouncement of judgment are protected as part of a defendants
right to a fair trial.
The court has an inherent power to regulate its own proceedings, however, and may hear a trial or
part of a trial in private in exceptional circumstances. The only exception to the open justice
principle at common law justifying hearings in private is where the hearing of the case in public
would frustrate or render impractical the administration of justice.10 The test is one of necessity. The
fact, for example, that hearing evidence in open court will cause embarrassment to witnesses does
not meet the test for necessity.11 Neither is it a sufficient basis for a hearing in private that
allegations will be aired which will be damaging to the reputation of individuals.12 The interests of
justice could never justify excluding the media and public if the consequence would be that a trial
was unfair.13
Rules 16.6‐16.8 of the Criminal Procedure Rules 2013 govern procedure where a court can order a
trial in private.14 A party who wants the court to hear a trial in private must apply by notice in
writing not less than 5 business days before the start of the trial.15 The application must be displayed
within the vicinity of the courtroom and give notice to reporters.16 The media should be given an
opportunity to make representations in opposition to the application.17 If the order is made, the
proceedings must be adjourned for a short period to allow for an appeal to the Court of Appeal
under s.159 Criminal Justice Act 1988.18
Hearing a case in private has a severe impact upon the general publics right to know about court
proceedings, permanently depriving it of the information heard in private. It follows that if the court
can prevent the anticipated prejudice to the trial process by adopting a lesser measure e.g. a
discretionary reporting restriction such as a postponement order under s.4(2) Contempt of Court
Act, it should adopt that course.**In making an application for a case to be heard in secret, a party
must explain why no measures other than trial in private will suffice.19
Often the adoption of practical measures such as allowing a witness to give evidence from behind a
screen or ordering that a witness shall be identified by a pseudonym (such as by a letter of the
alphabet) and prohibiting publication of the witnesss true name by an anonymity order under s.11
CCA (see below), will remove the need to exclude the public. Another possibility, where only a small
part of the witnesss evidence is sensitive, is to allow that part to be written down and not shown to
the public or media in court. However, measures such as these are also exceptional and stringent
tests must be satisfied before they are adopted.
The necessity test requires that even where a court concludes that part of a trial should be heard in
private, it must give careful consideration as to whether other parts of the same case can be heard
in public and must adjourn into open court as soon as exclusion of the public ceases to be necessary.
Circumstances which may justify hearing a case in private include situations where the nature of the
evidence, if made public, would cause harm to national security e.g. by disclosing sensitive
operational techniques or identifying a person whose identity for strong public interest reasons
should be protected e.g. an undercover police officer. The application to proceed in private should
be supported by relevant evidence and the test to be applied in all cases is whether proceeding in
private is necessary to avoid the administration of justice from being frustrated or rendered
impractical. Disorder in court may also justify an order that the public gallery be cleared. Again the
exceptional measure should be no greater than necessary. Representatives of the media (who are
unlikely to have participated in the disorder) should normally be allowed to remain.
[...]
Hearings from which the public may be excluded
 The general rule is that all court proceedings must be held in open court to which the public
and the media have access
 The court may hear trials in private in exceptional circumstances where doing so is necessary
to prevent the administration of justice from being frustrated or rendered impractical**
 Where lesser measures such as discretionary reporting restrictions would prevent prejudice to
the administration of justice, those measures should be adopted
 Where is it necessary to hear parts of a case in private the court should adjourn to open court
as soon as it is no longer necessary for the public to be excluded
 The embarrassment caused to witnesses from giving evidence in open court does not meet the
necessity test
https://www.google.co.uk/url?sa=t&s...ggkMAI&usg=AFQjCNEOCDdtTUqYZFqYZ7nNzqGxLzxa1w