GETTY The investigation team believe the operation was headquartered and run from Greater Manchester

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Earlier this month 24 suspects were collared across Greece, part of a joint investigation between the Mediterranean nation’s Organised Crime Unit and the UK’s National Crime Agency (NCA). In a linked police operation, nine people were arrested across the UK as intelligence agencies swooped on the gang, who targeted Iranians to bring to the UK. Chris Hogben, of the NCA, said it was likely “hundreds of Iranian migrants” had made their way to the UK using the gang, and estimated up 1,100 may have made it across the border. Officials have not yet ruled out “credible suspicions” that the network may be responsible for allowing terrorists into the Europe.

One of those arrested is suspected to be working for the Islamic State (ISIS), leading to suspicions ISIS fighters may have infiltrated the continent. An investigator said: “There’s no concrete evidence yet but the working assumption is that an Algerian terrorist in Spain was operating with an Algerian terrorist in Greece.” Houses were raided across Glasgow, Leeds, Manchester and Northampton earlier in December in a sting by UK police, assisted by three French police officers.

GETTY They bankrolled their illicit activities through counterfeit money and forged documents

The investigation team believe the operation was headquartered and run from Greater Manchester, with its tentacles and activities spread across the EU. As the nationalities of the suspected crooks spanned several countries, parallel investigations were also conducted in the Czech Republic, France, Greece and Spain. The gang are believed to have been smuggling Iranians into the UK, taking them on a route through Spain and France.

Migrants clash with police across Europe Wed, February 15, 2017 Migrants clash with each other in over crowded camps across Europe. Play slideshow EPA 1 of 107 Moroccan Police look at immigrants trying to jump the six-meter-high fence in Ceuta, Spanish enclave on the north of Africa, 09 December 2016.

The working assumption is that an Algerian terrorist in Spain was operating with an Algerian terrorist in Greece Investigator

The organised crime group are thought to have bankrolled their illicit activities through counterfeit money and forged documents, or impersonating the legitimate owner of the ID. Four forgery factories were uncovered in the operation, where it is thought the gang produced their counterfeit cash and papers, alongside forgery equipment, €50,000 (£42,000) in cash and hundreds of documents.

GETTY Investigators believe the gang were charging individuals a staggering €10,000 (£8,400)

Investigators believe the gang were charging individuals a staggering €10,000 (£8,400) to ply them with stolen or forged documents, as well as facilitating their journey into the UK. Europol, the European Union’s law enforcement agency, supported the operation.

They deployed a specialist mobile unit staffed with specialists in illegal immigration facilitation in a bid to crack down on the lucrative people smuggling industry. Over the past year millions of people have fled war-torn areas such as Syria and headed for the continent.

Land and sea crossings have been rife and fraught with danger, with countless images of bodies washing up on the shores of Europe and trucks stuffed with the rotting remains of migrants. Smuggling gangs preying on the migrants often charge eye-watering sums, promising to transport them into Germany, France and the UK among other countries, often on dangerous journeys which have left many dead.

GETTY The gang are believed to have been smuggling Iranians into the UK