A vast human tragedy is unfolding along the shores of the Mediterranean, its horrors largely ignored by Britain’s inward-looking, election-fixated politicians and an insouciant, slow-to-react European Union. Dozens of orphaned and malnourished children daily cry out for help; injured victims are thrown to sharks or forced overboard by religious fanatics; and hundreds die needlessly in this ruthless, expanding traffic in human suffering.

These grisly events are not occurring on the tourist beaches of Spain’s Costa del Sol, the French Riviera or the sheltered resorts of southern Turkey so beloved of well-to-do European holidaymakers. If they were, there would be more of a fuss. This tragedy has its origins, instead, in impoverished Chad, Darfur and Sierra Leone, in Eritrea and Somalia, in Syria and other war-ravaged countries of the Arab spring. And it reaches its usually unseen, often fatal denouement in the waters off northern Libya, as a growing number of refugees, asylum seekers and economic migrants desperately bids to reach Italy and Greece by sea.

The numbers involved are hard to gauge accurately. But it is clear the exodus, principally from Libya, is accelerating rapidly. Italian ships picked up about 11,000 migrants in the past week alone. Around 950 have drowned or been murdered so far this year, including about 450 in two shipwrecks last week. Although the overall total reaching Europe safely is similar, so far, to the same period last year, according to the International Organisation for Migration, the death toll is 10 times higher. As we report today, many are children who have been abandoned or sent on ahead by their parents in the hope of a better life.

Explanations for this developing tragedy are numerous. Libya, a failed state in all but name, is now embroiled in a multi-factional civil war. In the absence of effective governance, Islamist militias, including jihadis from Isis, hold increasing sway.

In these conditions, people-trafficking and smuggling gangs operate with impunity and readily resort to violence. Only last week the Italian navy was forced to storm a trawler that had been seized by armed men off Libya. The Vatican, meanwhile, condemned the alleged murder of 12 Christian migrants by 15 Muslims who were sharing their boat.

Migrants and refugees, the majority young men, are coming to Libya, the closest point to the Italian coast, and other staging points, from all over the Middle East and north and west Africa, driven by a range of factors. These include all-out war, Islamist insurgencies and climate change-related drought and famine. Rapid population growth, exacerbating a chronic lack of jobs and economic opportunity, is another powerful spur. The result has been called the biggest human upheaval since the Second World War. Mostly, these legions of the displaced are heading for Europe.

So what is Europe doing about it? The answer, so far, is dismayingly little. Instead of rallying around Italy’s admirable Mare Nostrum search and rescue programme, which plucked 100,000 people from the sea in 2014, the EU replaced it with a more limited border security operation run by its Frontex agency. So far this year, Frontex, by comparison, has rescued only 5,000 people. Monthly funding for its Triton programme is less than a third of the Mare Nostrum budget.

As the crisis deepens, Brussels’s dithering grows lethal. The European commission is due to publish a policy document next month, entitled Agenda on Migration. As its name and timing suggest, they are not in a hurry. Member states will consider a more collectivised approach to asylum and legal migration and the contentious idea of migrant processing centres in north Africa. Given the political sensitivity of the immigration issue in EU countries, and the eurozone pleas of poverty, the prospect of quick, effective action is remote.

Both Italy and Greece appealed urgently for increased financial help and practical assistance last week, as did Save the Children and Human Rights Watch. Jan Egeland, a former UN emergency relief co-ordinator, warned that the Mediterranean has become the world’s most dangerous border between countries not at war. He lambasted European governments for their inaction.

Meeting Barack Obama in Washington, Matteo Renzi, Italy’s prime minister, said the Mediterranean was a sea, not a cemetery. Obama promised to help, but his focus is on fighting Isis terrorism and stabilising Libya. From an American point of view, this seems understandable. This crisis on its doorstep is primarily a challenge for relatively wealthy Europe and its professed human rights values. If the EU cannot act collectively to counter such a threat to its shared security, borders and interests, then what, truly, is the EU for? But it seems few in Europe are listening. Europe’s politicians and the EU’s insulated, insular functionaries are shamed by their silence.

Before British Eurosceptics, Ukip included, use this failure to further write off the EU, they should reflect on Britain’s own inexcusably irresponsible response to the emergency. The government refused last autumn to support Mare Nostrum or Frontex’s replacement operation. Its argument, that search and rescue programmes only encouraged increased migration, has been totally discredited by this spring’s surge. Yet far from acknowledging their mistake, the Conservatives persist in ignoring what is happening beyond Dover. They will not or cannot see the bigger picture.

Their election manifesto makes no mention of the migration crisis in the Middle East and Africa or the link to non-EU immigration into Britain. Does home secretary Theresa May really believe the young men jumping lorries at Calais have materialised from nowhere, like shadow figures emerging from a hidden underworld? Does Nigel Farage really think Britain is alone in facing these difficulties, and that it alone can resolve them? And what does Ed Miliband, whose immigration policy focus has also been disappointingly domestic, propose to do about the wider issues? It is time such matters were included in the wider election debate.

The challenge is enormous. The fundamental causes of this crisis will take years to address. An urgent first step is to reinstitute EU-underwritten search and rescue operations. At the same time, as the UN has urged, a top priority must be to create safe, legal options so that would-be migrants do not need to turn to people smugglers or put their lives at risk at sea. More should be done, too, to broker peace in Libya. Britain and other EU governments have a joint responsibility, to victims and voters, to act swiftly to halt the mayhem in the Mediterranean.