More than 2,500 mainly Syrian and Afghan refugees, soaked and exhausted, reached the Greek island of Lesbos within hours on Wednesday, a sharp rise in the rate of arrivals via the dangerous sea crossing from Turkey.

They were the latest wave of at least 430,000 refugees and migrants, a record number, to have taken rickety boats across the Mediterranean to Europe this year, 309,000 via Greece, according to International Organization for Migration figures.

Around 50 rubber dinghies each carrying up to 60 to 70 people arrived in pouring rain in the space of five hours on one Lesbos beach, which was covered in life jackets and rubber tubes. Some refugees were suffering from hypothermia.