[Mike]

I guess we will have to respectfully disagree. The public can (IMO should) be regularly updated on camera by police services to reassure the public by a PIO, especially when you have a MAJOR INCIDENT that shuts down the center of major city. And that can be done without jeopardizing the sensitives of criminal activities. Its regularly done in Canada and the US even with domestic terror events.  Police are public servants, not a secret police agency, and IMO, public information comes with the territory today, especially in these days of mass/social media.  Its 2023 and speculation and disinformation can abound wildly.

I think I can speak with some authority on this subject, without listing specialist qualifications or the incidents I have had involvement in as a responder and in a command capacity for fear of doxxing myself. 

The police service's primary focus is to save lives, and prevent and detect crime. The ambulance service's job is to save life and limb. The fire brigade's job is to rescue, recover and save lives and prevent damage to property.
They can only release facts,  they cannot start answering questions on motive, cause or anything else while someone is in custody or a case is sub-judice. They cannot name casualties, or victims until it is certain that next of kin enquiries are well underway. Speculation will run riot in a case such as this - and a robust social media strategy should be set (agreed) along with a media strategy.

In a command structure (gold, silver, bronze - strategic, tactical, operational in plain English) the gold and silver set the overarching theme and a Bronze Media will be appointed (usually someone in the press office, however out of ours this may be a police officer themselves). They will release immediate information (utilising the Major Incident Public Portal for obtaining evidence, or through recognised newsdesk email addresses) as soon as they can do. I know first hand that the APP on press relations dictates that each statement released will be emailed to 'newsdesk@mediacompany.com' etc - they aren't holding back information, just releasing what they can, when they can. In the early stages of any major incident it is important that to save lives central to all decision making. This (I expect) would be called as a Plato incident; for those not familiar this is the police's nationwide response plan to a suspected marauding terrorist incident, bits of it are documented in the Manchester Arena Inquiry but in short it's go in, take the bad guys out, save lives - part of Plato is media but it's the tiniest part - the main part is sending specialist assets in, commanding the incident to end the threat and then any updates can be given. London Bridge (2017) is a good example of that - within 15 minutes the MPS, BTP and City Police all had statements out along the same line 'We are dealing with an incident, please avoid the area' - no further information was given - the incident was resolved within 8 of those 15 minutes. Questions that get considered are 'how many, where are they, do they have vehicles, are they a lone actor?' and others - briefing the public and media will always be scant and take time.

We aren't America, we can't give all the information all at once, there's legal issues to consider along with the risk of people wanting to go and have a look. One wrong line on a press release to feed the hounds/nosy can lead to a collapsed trial.

EDIT: Without saying too much, in my opinion it's likely the number of offenders was not known - and that may explain the lack of information given early on - if you think you've got more than one person in a Plato incident you aren't going to be tweeting and giving info to the media.

I apologise this isn't pres related but does have a bearing on the speed of information flow from Nottinghamshire Police.