The officer in charge of one of the largest security operations in British history at the forthcoming Nato summit in Wales has said the high-profile event is "completely unchartered territory" for UK policing.
Assistant Chief Constable Chris Armitt, who has been seconded to Gwent Police from Merseyside Police to oversee the policing operation, said some 9,500 officers from across the UK have been drafted in for the event.
While the focus of the summit is at the Celtic Manor resort outside Newport on September 4 and 5, events will also be taking place in Cardiff, while the 150 visiting dignitaries, which include an unprecedented 67 heads of state, will be staying in hotels from Swansea to Swindon, including Bristol, Bath, Gloucester and Cheltenham as well as Newport and Cardiff.
Mr Armitt, who has been in post for eight months planning the response, also warned arrests are expected as a small number of protesters are understood to be planning a march to the Celtic Manor resort itself - which is surrounded by 13.5 kilometres of security fencing.
Speaking at a briefing in London, Mr Armitt said: "We're anticipating some protest activity at this event.
"The overwhelming majority of that will be lawful, it will be peaceful, we will facilitate it and we are in liaison with a number of groups who have expressed a desire to come and protest either ahead of the summit or indeed on the first day of the summit itself.
"And I think unfortunately we will see a smaller, more difficult protest footprint, people intent on taking some form of direct disruptive action or who maybe intent on committing some acts of damage."
A march is planned on the streets of Newport on August 30 finishing with a rally and speeches, which Mr Armitt said was "perfectly lawful and legitimate protest activity".
However, he added that "something a little bit more challenging" is expected for the day of the summit.
"We think we might see something a little bit more challenging, people who express a desire to go to the Celtic Manor," he said. "The reality is they will not get to the Celtic Manor, they will encounter the security framework around the summit site.
"Any attempt to breach that will result in people being arrested because they will be committing acts of damage and they will be committing public order offences."
Mr Armitt said the number of heads of state and foreign secretaries, who are both subject to armed protection under terms in the Vienna convention, meant this was "unchartered territory for UK policing".
Of the 9,500 officers, 1,500 will be from Gwent and South Wales Police and a number will come from Wiltshire, Avon & Somerset and Gloucestershire, which fall under the operational footprint, although all 43 forces in England and Wales, Police Scotland, Police Service of Northern Ireland, British Transport Police, Ministry of Defence Police, Civil Nuclear Constabulary and officers from the Channel Islands are joining the operation.
In the Welsh capital, Cardiff Castle and the Royal Welsh College of Music and Drama will be subject to security measures, while a smaller operation will be present at Cardiff Bay where seven Nato war vessels will be present.
All 28 Nato countries are attending, as well as International Security Assistance Force (Isaf) nations and Nato partner nations.
In addition to dignitaries, some 10,000 staff and 2,000 media are expected.
Mr Armitt said the burden of the cost of the operation does not fall on the contributing police forces but is centralised.
He went on: "The protected persons is the very unusual aspect with this because the event is focused on heads of state and foreign secretaries and they are the two diplomatic positions that are encompassed under the Vienna Convention then you almost get a double whammy in terms of armed protection for each country coming."
The summit will focus on the situation in Afghanistan, the Russia-Ukraine crisis and Nato's future role under the theme Building Stability In An Unpredictable World.