Drug mules are “brazenly” flying into the UK with suitcases stuffed full of cannabis without even trying to hide it, according to National Crime Agency (NCA) bosses.

Director general Graeme Biggar said cannabis remains the “biggest single drug consumed in the UK” and told how the law enforcement agency had noticed a “significant increase” in the last two years of airline passengers trying to bring the drug into the country in their luggage.

As he outlined the NCA’s annual assessment of crime threats to Britain, he told reporters: “One thing that has been really striking for us over the last 18 months has been the extent at which people are trying to bring cannabis into the country as air passengers in their own luggage.

“Cannabis and actually cocaine, but particularly cannabis, recently, and we’ve seen really quite significant increase.”

He said this year officers had seized “more than double” the amount of cannabis confiscated in 2023 from air passengers as they fly in.

“We are seeing people brazenly just having entire suitcases with nothing in them, apart from cannabis, and that is something we just didn’t see two or three years ago.

“In terms of overall supply in the UK, that’s not that material. We’ve seized 12 tonnes so far this year, and that is really quite a small proportion of the amount of cannabis that’s consumed in this country.”

The “vast majority” of cannabis is still grown in this country and it is chemically the same composition regardless of where it comes from and is cultivated, but there is a “perception” in the drugs market that when obtained from countries where the drug is legal that it is of better quality, Mr Biggar said.

“It’s not, it’s the same chemical composition. There’s really no advantage to getting your cannabis from overseas. So, I think that’s why there’s a bit of a demand for it.

“We used to see people when they were trying to bring drugs into the UK, going to great lengths to hide them within bags or by ingesting them, which we absolutely still get. But it’s just much more brazen now, an entire suitcase, and we have had cases, including very recently, of multiple suitcases.”

Rob Jones, the NCA’s director general of operations, said: “What we are seeing and what really worries us is a normalisation of in bags that have gone through very stringent security controls, literally, a wheelie bag with 40 kilos of cannabis in it. We have seen flights with 10,16, bags with half a tonne of cannabis on one flight. That would have been a freight importation. This has been brought by couriers. That is the step change we’re seeing.”

Some cocaine couriers are “using similar methodology with much higher quantities, just running the gauntlet and playing the numbers game”, he said, adding: “Now that’s all preventable, because an X-ray of the bag filled with 30 kilos of cannabis is so obvious, it’s just a vacuum packed block of drugs. And that is preventable, and that’s what we need to we need help stopping while we focus on the more sophisticated.”

Border Force is “finding it and we’re investigating it”, he said as he stressed this was a problem seen on flights coming into the UK after overseas customs and security checks have been carried out.

Mr Jones said: “This is outbound customs controls and outbound security controls. So, for instance, if you leave Thailand and transit through Europe, you’ve checked your bag in Thailand, and then it’s been through a transit area in another airport and come on a short-haul flight.

“That’s two layers of aviation security controls designed to detect drugs, bombs, guns, where you’ve got bags full of contraband that just whistle through. And so this isn’t so much a customs issue as a security issue. It’s really the outbound and transit security.”

Mr Biggar added: “It’s stopping it getting on the plane at the other end.”