I'm in a badly-lit, untidy room with dull yellow walls splattered with the kind of notices you find on any industrial site.
It's crowded with people pushing trolleys of parcels, people opening deliveries with the icy zip of a stanley knife, people making entries into computers, people weighing things, people testing things.
This is the frontline of a war - a battle to stop the flow of illegal prescription drugs sold over the internet. Agents from the drugs watchdog, the MHRA, and the Border Agency are searching suspect parcels - suspicious because something showed up on X-ray.
We're filming under tight security constraints.
I can't tell you where this international parcel hub is, or who runs it. I can't show you the faces of the agents. But I can tell you it's working. Over a week, they have seized 1.25 million doses of illegal prescription drugs sold from websites linked to organised crime.
It's part of Operation Pangea, a global attack on illegal medicines co-ordinated by Interpol and the MHRA and involving a hundred nations. In the UK alone, they've seized over 2 million doses, valued at £3 million, shut down about 500 websites and raided private addresses. We went with the police and MHRA agents on a raid on a web dealer in north London. It's in a leafy, quiet street of huge Victorian houses converted into rabbit-hutch flats.
The dealer turns out to be small fry. They find evidence of PayPal transactions for about 20 deals. But these small fry are just the public face of a much more sinister operation - connected to networks of organised crime. Nimo Ahmed, the MHRA's head of enforcement, tells me they're based in Eastern Europe, mainly Russia. In the past, they've had little co-operation from the authorities there. But he thinks things are changing and they could be beginning to close in on what he calls "the real bad guys".
And why, you might ask, is buying prescription medicines on the internet such a bad thing? Because you don't know what you're getting and what you're getting could be dangerous for you.
One example. At the parcel hub, they seize 150 boxes of a Chinese herbal remedy for erectile dysfunction. It claims to have none of the side-effects of "synthetic western medicines".
But when they test it on the spot, they find it contains the same active ingredient as Viagra. If you have a heart condition that might be extremely dangerous. And you might have turned to a herbal remedy precisely because you have a heart condition that means your GP wouldn't prescribe Viagra.
Watch Lawrence McGinty's report in full below.
If you think your medicine might be fake contact the MHRA hotline on 020 3080 6701 or email email@example.com