An international operation to crack down on the internet trade in counterfeit and unlicensed drugs has resulted in the seizure of £6.5m (€8m; $10.5m) worth of pharmaceuticals worldwide and the closure of 18 000 illegal online pharmacy websites.

Operation Pangea V involved police, customs, and national medicines regulators working together in 100 countries. The weeklong operation, coordinated by Interpol, led to 86 people being arrested or placed under investigation worldwide.

Nimo Ahmed, acting head of enforcement at the UK Medicines and Healthcare Products Regulatory Agency (MHRA), described it as the most successful operation against the illicit trade in pharmaceuticals ever carried out.

The operation, named after the term for the supercontinent when Africa, Europe, and the Americas were still joined together, was instigated by the MHRA in 2006 as a UK “internet day of action” and expanded in 2008 to an international day of action involving eight countries. The next year it became an international week of action. This year it involved more than 100 countries.

This year’s operation for the first time …