Another court hearing will be held later today ahead of inquests into the deaths of 22 people murdered in the Manchester Arena terror bombing.
The pre-inquest review, the fourth, will be attended by some of the families of those killed by suicide bomber Salman Abedi, 22, at the end of an Ariana Grande concert on May 22 2017.
Jane Tweddle, 51, Georgina Callander, 18, Michelle Kiss, 45, and Saffie Roussos, 8 - all from Lancashire - were all killed in the attack.
The hearing, which will partly be held in private, will discuss whether sensitive national security information can be heard in public when the inquests are held next year.
The bomber's younger brother, Hashem Abedi, in Libya at the time, was extradited from Tripoli in July and will go on trial at the Old Bailey in November. He denies 22 counts of murder.
The full inquests, scheduled to begin in April 2020, will examine the build-up and the attack itself, security arrangements at the arena, the emergency response and the victims and their cause of death.
They will also look at whether the attack could have been prevented, as well as the role of the police and security services.
The inquests were first opened in 2018 before retired High Court Judge, Sir John Saunders, with three separate hearings held in October 2018, February 2019 and July 2019.
On Friday lawyers for the Government, police and others will discuss the question of Public Interest Immunity (PII) - whether sensitive information relating to terrorism and national security is heard before the press and public at the inquests.
Part of the hearing will be held in private, with public and press excluded during "closed" sessions.
Lawyers for families of the victims have called for "transparency" even though some evidence could cause "embarrassment" to the security services, police and others.
Applications for PII have been made by the Home Office and Greater Manchester Police (GMP).
The first part of the hearing will be open to members of the media and the public who can attend at Manchester Town Hall.
The second part of the hearing will be closed and will be held at another undisclosed location.
Unusually, the coroner and lawyers representing GMP and the Government will be live-streamed from the other location to the Town Hall for the open session.
The pre-inquest hearing will begin at 10am at Manchester Town Hall.