•The National Crime Agency (NCA) said 32-year-old Harem Ahmed Abwbaker was arrested at an address near Cheltenham, southwest England.
•He is suspected of being "a member of the organised crime group who conspired to transport the migrants to the UK in a small boat".
UK police on Tuesday arrested a man suspected of playing a "key role" in the deaths of at least 27 people who drowned attempting to cross the Channel in a dinghy last November.
The National Crime Agency (NCA) said 32-year-old Harem Ahmed Abwbaker was arrested at an address near Cheltenham, southwest England.
He is suspected of being "a member of the organised crime group who conspired to transport the migrants to the UK in a small boat".
NCA investigators are working with the French authorities to track down those responsible for the tragedy.
French prosecutors have so far charged 10 people for their alleged role in the disaster on November 24 last year.
It was the worst accident in the Channel since the narrow strait became a key route for migrants from Africa, the Middle East and Asia attempting to reach England from France.
The vessel sank after leaving the French coast, leading to the death of all but two of those aboard. Four people remain missing.
The suspect will appear before London's Westminster Magistrates Court on Wednesday, where extradition proceedings to France will commence.
Charges faced there include the French equivalent of manslaughter and facilitating illegal immigration.
"This is a significant arrest and comes as part of extensive inquiries into the events leading to these tragic deaths in the Channel," said NCA deputy director Craig Turner.
"The individual detained today is suspected of having played a key role in the manslaughter of those who died.
"Working closely with our French partners we are determined to do all we can to get justice for the families of those whose lives were lost," he added.
Among the 27 -- aged seven to 47 -- were 16 Iraqi Kurds, four Afghans, three Ethiopians, one Somali, one Egyptian and one Vietnamese migrant.
Tributes and demonstrations took place on Thursday for the 27 victims of the tragedy that France's interior minister admitted should have been prevented.
Several boats packed with rescuers and local elected figures took to sea off the coast of Dunkirk to mark the anniversary.
"It's a tragedy that we were expecting and there will probably be others," said the head of the local branch of the SNSM lifeboat service, Alain Ledaguenel.