Britain is a country that "doesn't walk on by", David Cameron said as HMS Bulwark undertook another rescue mission off the coast of Libya.
Arriving at the G7 summit in Germany, the Prime Minister said the flagship had been deployed because Britain is a "country with a conscience".
"HMS Bulwark, the Royal Navy flagship, is in the Mediterranean because we want to save lives," Cameron said.
But he warned, "We need to deal with the causes of this migration, not simply with its consequences."
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.