HMS Bulwark has begun a rescue mission to save at least 500 migrants found in four boats in the seas off Libya.
"From first light this morning, a Merlin helicopter from 814 Squadron onboard HMS Bulwark has been conducting surveillance operations and has identified four migrant vessels in distress, containing a total of at least 500 people," a Ministry of Defence spokeswoman said.
"HMS Bulwark has now commenced rescue operations to recover those in the vessels."
It is estimated that more than 1,600 people have drowned so far this year trying to make the crossing.
Hundreds of migrants were rescued from the Mediterranean at the weekend - but their journey will not stop there, as they tell ITV News.
Britain's flagship HMS Bulwark has been involved in its "largest operation to date", plucking more than 1,000 migrants from makeshift boats
As HMS Bulwark continues to rescue migrants in the Mediterranean, David Cameron pledged that Britain would not shirk its responsibilities.