Deputy Assistant Commissioner Dean Haydon, Senior National Coordinator for the Counter Terrorism Policing network, has this morning declared the incident a terrorist incident, and CTPSE will be taking over the investigation.
Chief Constable John Campbell of Thames Valley Police said: “I am deeply saddened by the events of last night.
“This was a truly tragic incident and the thoughts of Thames Valley Police are with all those who have been affected.
“Incidents of this nature are very rare, though I know that will be of little comfort to those involved and understand the concern that this incident will have caused amongst our local community.
“Police cordons continue to be in place and are likely to be for some time as CTPSE work further to investigate this incident and establish exactly what happened.
“I would urge the public to avoid the area at this time and thank the community for their patience. We will let you know as soon as the area is back open.
“I would also ask that the public avoid speculation.
“We would like to hear from anyone who has video footage. Out of respect for those deceased and injured, along with their loved ones, please do not circulate this footage on social media – this will be incredibly distressing.
“If you have any information about this incident, please contact us on 101 quoting reference 1159 20/6.”
Counter Terrorism Policing will make a further statement later today.