A 150-Strong task group of Royal Marines has been sent to the Mediterranean in preparation for Britain's stepping up operations against Libyan people-smugglers sending boatloads of migrants to Europe.
The specialist unit trained in boarding and searching small craft has been moved into position as European nations try to halt the migrant crisis in which trafficking gangs have sent hundreds of thousands of refugees into the sea on flimsy and overcrowded boats.
The Foreign and Defence Secretaries will today meet their European counterparts in Luxembourg to discuss escalating the EU's anti-smuggling operation in the Mediterranean.
Sources said the Royal Marine Special Purpose Task Group (SPTG) was likely to play a key role in the next phase of the EU's anti-smuggling operation, Operation Sophia.
Ministers want to smash trafficking gangs by capturing traffickers as soon as they leave the Libyan shore. Earlier efforts have so far been undermined by warships being unable to enter Libyan territorial waters, but leaders are hoping a newly appointed unity government will give permission for Operation Sophia to approach the coast.
The task group is formed around Zulu Company of the Arbroath-based 45 Commando Royal Marines.
So far, around 24,000 migrants have arrived in Europe from Libya, where trafficking gangs have exploited the country's chaos.
Officials expect the Libyan smuggling route to Italy to again become the main route into Europe this summer as deportations from Greece to Turkey deter migrants from eastern Mediterranean paths.
Matteo de Bellis, of Amnesty International, said: "We should expect tens of thousands to attempt to depart this spring and summer bound for Lampedusa. With the closure of the EU-Turkey border to migrants, we may learn once again how closing one route pushes people to another route."
European defence chiefs are also expected in the coming weeks to pave the way for a possible military intervention to bolster the Libyan government against Islamic State militants. Officers will hold planning talks in Rome to discuss how many troops are likely to be needed to support the new UN-backed government, and train security forces.
America's envoy this weekend urged the new unity government in Tripoli to accept international help, suggesting time was short to combat militants who have seized swathes of coastline.
Ministers are considering sending up to 1,000 British troops to join an Italian-led mission training the Libyan army, as well as a separate mission to tackle trafficking gangs on the coast.
A formal decision is waiting for a request for help from Libya's new government.