Why is there still a migrant crisis in Europe?

This year almost 100,000 people have arrived in Italy by boat - and more than 2,000 have died trying. The Italians say they can’t cope, but it's a problem which has now been going on for years - so why has nobody solved it?In this week's programme David Aaronovitch asks who are the migrants, where are they coming from, how do they get to Europe and what needs to be done to stop more people dying. CONTRIBUTORSJoel Millman, UN's International Organisation for MigrationTuesday Reitano, Global Initiative against Transnational Organised CrimeMattia Toaldo, European Council on Foreign RelationsElizabeth Collett, Migration Policy Institute Europe