The man charged with policing the Nato Summit held in Wales in September has spoken for the first time about an intelligence-led operation that led to stun grenades being destroyed an hour before they were set to explode in the path of world leaders.
In an interview with The Police Oracle Merseyside Police Assistant Chief Constable Chris Armitt said officers averted what could have been a "catastrophe" when they discovered smoke bombs and stun grenades hidden in vegetation lining the road protective diplomatic vehicles were due to take to Cardiff Castle.
ACC Armitt, who held the position of Gold Commander during the summit in South Wales, said "very high profile individuals" had been due to use the road.
He added, "There is no doubt that if a stun grenade had been dispatched as a convoy went past we could have had a very significant response from the visiting close protection officers from all the nations.
"Our ability to control their response if they thought that transport was under attack is questionable.
"We were fortunate, with a really good intelligence-led operation, to get that kit about an hour before it was due to be deployed."
The eleventh hour recovery of the explosives "knocked the stuffing" out of the groups believed to have been responsible, ACC Armitt said without naming them.
There were, however, two "totally random" attacks on police officers said ACC Armitt, including a female officer who was assaulted in Cardiff - incidents described by ACC Armitt to violent protesters' "frustrations".
Political pressure senior officers felt under because of tensions between the Welsh government and Whitehall was also a serious issue.
ACC Armitt said: "This event took place in Wales, and policing is the only non-devolved government structure in Wales.
"Cardiff city centre is a really nice city centre with a lot of high end shops - a fantastic target for anti-globalisation type protests. The nervousness around that was acute to put it mildly. We were balancing that nervousness with the desire in Westminster to deliver as high profile an event as possible."
He added: "We were not the event organisers, but at times it didn't feel that way. We were very much front and centre of making this thing work."
ACC Armitt offered a rare behind-the-scenes picture of the challenges of policing such a sensitive event and helping President Obama make an "unannounced" visit to Stonehenge.
"On the evening of September 4th the US president, totally unannounced, informed the UK Government he was going to Stonehenge on his way back to US Air Force base Fairford, where Airforce One was going to fly out from," said ACC Armitt. "It's not on his way back to Fairford. It's one hundred and something miles in the other direction.
"That obviously posed something of a challenge."
With the help of the military, police were able to search the area and facilitate the visit so Mr Obama could tick this item off his bucket list, he added.