THE police chief in charge of operations for the Nato Summit has said explosives were discovered just an hour before they were set to go off on a route to be used by world leaders.

The Police Oracle has reported that Gold Commander Assistant Chief Constable Chris Armitt revealed at a policing conference last week that an intelligence-led operation discovered stun grenades in vegetation lining a road "high profile individuals" were due to take to Cardiff Castle.

ACC Armitt told Police Oracle: "There is no doubt that if some thunder flashes or a stun grenade had been dispatched as a convoy went past we would 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."

ACC Armitt said the groups believed to be responsible for planting the explosives got "a bit weary of being overpowered, outnumbered and outgunned" after the discovery and it "knocked the stuffing" out of them

It was also revealed that there were two "totally random" attacks on police officers, including a female officer who was assaulted in Cardiff.

He added that President Barack Obama's wish to visit Stonehenge before returning back the US was "totally unannounced".

He added: "On the evening of September 4 the US president decided to tell us he was going to Stonehenge on his way back to US Air Force base Fairford, where Airforce One was going to fly out from.

"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."

Police, with the help of the Armed Forces, were able to search the area and accommodate President Obama's request.

The Nato Summit saw 60 world leaders descend on the Celtic Manor Resort in Newport on September 4 and 5.