Prince William joked that cannabis has "a pretty good and strong smell" when he was taken to a room full of contraband.
The 36-year-old Duke of Cambridge was surprised by the amount of drugs and weapons intercepted by border staff and officials while visiting the Royal Mail International Logistics Center at Heathrow Airport.
After five minutes in the room, which was filled with packages of cannabis, MDMA and cocaine, the king joked: "We'd better get off before we go through a drug test!"
The visit to the jail was part of William's visit to the center to see in action the fight against the illegal trade in wildlife.
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Prince William, 36, returned to his busy schedule on Thursday, when he visited the Royal Mail World International Logistics Center at Heathrow Airport
Prince William watches as a United Kingdom Border Force officer scans incoming mail and packages through the X-ray machine to the UK for contraband items during a visit to the Royal Mail international distribution center near the airport of Heathrow
While walking, the border force officer, Steve Harrington, said: "Excuse the smell."
The dungeon was full of marijuana packages of herbs and other drugs, as well as seized weapons and wildlife products.
& # 39; These are drugs that we get here, large cannabis seizures. It comes from the United States, where it is legal in some states, "Harrington said.
William joked: "It's a good strong smell."
Harrington said the 545 packets of drugs and 1,657 weapons, including stun guns and knives, had been seized in the past month.
While they showed him the weapons, which filled a wall of the room, the Duke said: "It is an amazing amount of weapons in a month." That is quite impressive. "
Prince William smiles as he talks to workers at the Royal Mail sorting office during a visit to the Royal Mail international distribution center near Heathrow Airport in Slough
William watches as an officer of the United Kingdom Border Force scans incoming mail and packages through an X-ray machine
Prince William talks to workers at the Royal Mail sorting office during a visit to the Royal Mail International Distribution Center near Heathrow Airport in Slough
The center also receives MDMA from the Netherlands, cocaine and the occasional package of heroin from Pakistan.
Although the smell of cannabis was remarkable, Harrington said: "I agree, some people do not like it, but I do not spend all day here.
Clive Perry, the senior Border Force officer who showed William about the seizures, added: "To be honest, I think my officers have become immune to that." We process it and move it as fast as we can.
& # 39; He [Prince William] I mentioned it, it's something you can not ignore. I think the smell of paint disappeared there, because we had it decorated for his arrival, which is why cannabis has overwhelmed him. "
Prince William watches as Border Force officers unfurl a snake skin that was confiscated on his way to the UK
Perry said the center, which only deals with packages less than 2.2 kg, had seized hundreds of kilos of cannabis since April. & # 39; We received a lot. The volume of material that arrives through the publication is quite high. "
Cannabis and other drugs such as cocaine can be detected by trained personnel, he said. Royal Mail staff detect suspicious packages, and Border Force officers pass them through X-ray scanners.
"The work we do with Royal Mail: we give them keywords to look for when they look in the mail, they put those packages aside, and then we verify it and find it.
"It's about looking at X-ray images to see what the powders look like, the best example is birthday cards with a distributor bag in. It's easy to identify with an X-ray image."
William visited the center to highlight the work of Royal Mail as a member of its United for Wildlife Taskforce, which combats the illegal trade in wildlife.
The father of three children attended the site to see how they avoid trafficking in illegal wildlife products, meeting with the team behind the operation
Knowing the team behind the organization, William has been outspoken in his passion for the industry, making the wildlife campaign one of his main charitable goals.
Prince William visits the Royal Mail World International Logistics Center at Heathrow Airport to see how they avoid trafficking in illegal wild products
He was shown four packages confiscated this week: two from Thailand and two from Great Britain for China and Hong Kong.
One of Britain's packs contained several ivory artifacts, including a pair of binoculars, and a snake skin believed to be from a rock python. "I would not have liked to meet the snake that was using that," said the duke. "It's amazing what you find, it really is."
The seized weapons that were shown included an extendable baton and a pair of knuckles. Mr. Perry told the duke: "The other weekend we had 500 knuckles at one time. Unpleasant weapon We also get many movie knives. "
He was also shown the skull of an arctic wolf, which will probably be used as a training aid.
The weapons are kept for a month and then recycled, while the drugs are kept for a month and then incinerated.