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@brianwhelanhack @mikebowtie @TheGlazingGuru Actually, Brian, they do. Always. For operational reasons. They used to release them, but they stopped as it was contentious. But they still give unofficial estimates privately. And they always do two calculations. The first is based on special calculations and a rule of thumb >
@brianwhelanhack @mikebowtie @TheGlazingGuru >assumed density of 3.5 people per square metre. They then, however, continue updating this estimate with a second stage calculation that looks at people still joining the back of a march and an updated density ratio based on how long a demo takes to get between two fixed points>
@brianwhelanhack @mikebowtie @TheGlazingGuru >That is why final estimates often differ. Because some matches are much more tightly packed and slow moving than others. This updated ratio can change the calculation dramatically. In this case, the 1m estimate first surfaced before the front started moving. After that point>
@brianwhelanhack @mikebowtie @TheGlazingGuru >and this is very important, the police advised the front of the march to start moving annhour earlier than they had intended, because they were experiencing “unusually high density and rate of people joining at the back” and became concerned. People continued arriving in a>
@brianwhelanhack @mikebowtie @TheGlazingGuru >regular stream for at least two more hours. And according to everyone on the march it was unusually tightly packed and slow moving. This makes the original 1m estimate, very unreliable. But having released it, I suspect, organisers did not want to update, as they would face>
@brianwhelanhack @mikebowtie @TheGlazingGuru >accusations precisely like this. 1m is a great, iconic number anyway. At the end of the march the police unofficial rough estimate to organisers was closer to 2m. Had this confirmed by two separate sources. It may be wrong, but it’s more reliable than the static 1pm figure. END
@brianwhelanhack @mikebowtie @TheGlazingGuru Also, please note that *all* the main campaigning groups have recently updated their estimate to say “over 1m” or “1m+”.
