The National Crime Agency has launched one of its biggest operations to tackle a people smuggling network involving suspected Kurdish gangsters.
Some 350 officers took part in raids in the Northumbria, Cleveland, Sussex and Metropolitan Police force areas.
They targeted around 20 addresses and visited car washes to monitor activity following a year-long investigation with links to the French, Belgian and Dutch authorities.
Officers from Immigration Enforcement, HMRC and the Gangmasters and Labour Abuse Authority were carrying out spot inspections of car washes.
A suspect was arrested at a house in Middlesbrough during the operation (Tom Wilkinson/PA)
Officers at a briefing at Cleveland Police's HQ in Middlesbrough were told they were looking to arrest two specific men around Teesside suspected of being involved in bringing migrants into the UK in lorries for money.
The gang is suspected of charging up to £10,000 per head to smuggle migrants across the Channel.
The authorities' car wash inquiries were aimed at disrupting the gang's money laundering operation.