On Tuesday, 846 migrants were rescued at sea in Sicily – including 120 women and 40 children. A dead body was also recovered off the coast of Libya, bringing the number of casualties up to eight since the weekend.

The new arrivals bring the total number of migrants rescued in the Mediterranean to more than 15,000 since the start of the year, according to the International Organisation for Migration (IOM).

Why are migrants heading for Europe?

Over the past couple of years, Europe has seen increasing waves of migration as Syrians and sub-Saharan Africans cross the Mediterranean. From unrest in Libya, civil war in Syria and the rise of Islamic State militants in Iraq, thousands of refugees have been forced to leave their homes in search of better lives.

The UNHCR says that at least 50 per cent of migrants arriving in Europe are people in search of asylum. As well as civil conflict, migrants from Eritrea, Somalia and Ethiopia are heading to Europe to escape poverty.

How many migrants are we talking about?

In 2014, almost 219,000 people crossed the Mediterranean, three times higher than the previous peak of 2011 when the Arab Spring was in full swing. In Italy, more than 170,000 people arrived by sea, mainly from Eritrea and Syria.

There are two other major sea routes, leading to Spain and its Ceuta and Melilla enclaves, and to Greece, mostly from Turkey. Over 3,500 people died or went missing in the Mediterranean in 2014, making it the deadliest year of all. So far, in the first three months of 2015, around 480 people have lost their lives or gone missing.