Police have said they were forced to close Dover port for seven hours after a security alert because the potential risk to public safety was so high.
Ferry services from Dover have returned to normal after delays
Thousands of passengers faced lengthy delays following the discovery of prohibited weapons, thought to be guns, in a car arriving on a ferry from Calais on Friday evening.
Kent Police have been granted more time to question three British men arrested in connection with the weapons find.
The port was closed to traffic for seven hours as Army bomb disposal experts spent several hours examining the car in the customs surveillance area of the eastern docks.
A Kent Police spokesman said the long closure had been necessary despite the disruption to passengers.
He said: "The reason it had the effect it did was because of the location.
"Clearly if it had happened somewhere else it would not have caused such a large knock-on effect.
"If you have - especially in the current climate - reason to believe there is a possible threat, then public safety is uppermost and you have to ensure that all necessary precautions are taken.
"Had it not been necessary then we would not have done it.
The port was closed to traffic while Army bomb disposal experts worked
"We are mindful that it is one of the busiest ports in the world and we tried to keep the delay minimal as long as it is consistent with public safety.
"We are not going to cut corners when public safety is at risk."
He said he could not give any more details about the weapons found or the people arrested for "operational reasons".
The weapons were found during a routine search using X-ray equipment after the car was stopped at 1921 BST on Friday.
The three men were initially held under the Terrorism Act, but British security sources have told the BBC the matter is now being treated as a "police matter" rather than an intelligence operation.
At the height of the security alert 10 ships carrying several thousand passengers were left stranded out in the Channel between Dover and Calais waiting to dock.
Another four that were inside the port when the alarm was raised were delayed by several hours.
Services had mostly returned to normal on Saturday morning, with only SeaFrance reporting delays until mid-morning.
Roads became jammed as motorists travelling to catch overnight ferries were unable to reach the port because of a 400-metre exclusion zone set up on the port site.
The traffic began to clear after roads into the port were re-opened to incoming vehicles at 0245 BST.