The ringleader of people smuggling ring who illegally brought thousands of mostly-Iranian nationals into the UK has been apprehended at Heathrow airport.

More than 100 people were arrested across Europe in an operation targeting the ring, involving Spain’s federal police and the European crime agency Europol working alongside London’s Metropolitan Police.

It is claimed that the gang helped more than 200 people a year illegally enter the UK for ten years, The Times reports.

Operating from the south of Spain, the smugglers charged the migrants around €25,000 (£22,500) and gave them passports bought from Spanish citizens and forged identity documents to allow them to travel from Spain through European airports.

The investigation was launched last year when four Iranians were discovered trying to fly from Hamburg to Britain using false documents, Europol said.

Spanish police said the criminal organisation was 15 people-strong, all of whom had been detained. Dozens of Iranian nationals were also arrested at European airports, after being found carrying the forged passports.

A spokesman for Europol said: “The leader of the criminal group was arrested by the Metropolitan Police after a European arrest warrant was issued.

“The group was perfectly structured and each member had a defined role, ranging from recruiting the migrants in their country of origin, to facilitating the transfers, hosting them in safe houses in Spain, and supplying the travel documents.”

Spain’s Policia Nacional said: “With the dismantling of this criminal organisation, the illicit trafficking of Iranian citizens to the EU and the United Kingdom has been considerably reduced.”

Towards the end of last year, Spanish police broke up another people trafficking gang who illegally smuggled at least 6,000 Ukrainian migrants into the UK.

The gang charged €2,500 (£2,100) to traffic the Ukrainians across the continent and made at least £13 million offering illegals visas, false passports, plane tickets, and accommodation in transit countries.