The true figure may never be known, but maybe as many as 900 illegal migrants, the majority women and children trapped below decks, drowned when an unseaworthy fishing boat capsized on Saturday in Libyan waters. The Tunisian master and Syrian mate of the doomed vessel have been arrested by the Italians, who managed, however, to save only a handful of the passengers. The master is being charged with culpable homicide. There is an almost palpable sense of relief in Brussels that the authorities have caught someone upon whom blame can be fixed for this massive human tragedy - at least 1,600 migrants have drowned so far this year. There will probably be some disappointment that neither of the seized people smugglers is Libyan. Because Libya is the heart of the problem. Of the more than 165,000 migrants picked up last year, 85 percent of them left from Libyan shores. A UN report suggests that in 2014, Libyan smugglers earned $174 million from the sea voyages alone. Further back down the human trafficking route, similar sums are being produced for a network of armed gangs who pass the migrants between them. And it is upon Libya that EU foreign ministers will be focusing when they hold an emergency meeting in Brussels on Thursday. A ten-point plan was unveiled on Monday, which is likely to form the basis of a program of action. There are two particularly controversial points. The first is that measures should be taken against the smugglers' craft. The second is that migrants who have no political grounds to seek asylum in Europe will be sent home. The latter proposal runs serious risks in terms of human rights. While on the face of it, it is perfectly reasonable to return “economic” migrants to their countries of origin, such a policy is fraught with political risk. Civil rights organizations will be watching the whole process like hawks and the minute something goes wrong - a returned migrant arrested or killed - the protests will be deafening. But of more concern is the idea that some steps should be taken against the vessels that the smugglers are using. It suggests some sort of military action either to bottle up craft in Libyan ports or even to destroy them. The majority of migrant vessel departures are from the long coast between the border with Tunisia and Misrata. The rebel Libyan Dawn government which last summer seized Tripoli, the capital, claims to be in control of this territory. Given the criminality of the militias that support it, this may be the truth, in that they are getting a share of the people smugglers' profits. Nevertheless, if EU warplanes sought to put out of action the dwindling number of Libyan fishing boats (smugglers are reportedly trying to buy vessels in Egypt and Tunisia), it would be an infringement of Libyan sovereignty, unless the internationally-recognized government and parliament in the east of the country, made a formal request for action. The EU is on surer ground in destroying the craft from which they rescue migrants. Last month, armed smugglers forced the Italian coast guard to hand back a vessel from which 140 people had just been rescued. A warplane should have been called in to destroy the smugglers' craft along with the greedy merchants of misery aboard it.