Frans Timmermans sent the shock warning to European Union colleagues, declaring the bloc was "on the brink" and that “the unthinkable has become possible.”
The first vice-president of the European Commission, standing in for his boss Jean-Claude Juncker, launched a devastatingly honest speech attacking the EU’s handling of migration and warned the break-up of the bloc was now a realistic prospect.
Following on from Dutch prime minister Mark Rutte's demand for action, Mr Timmermans said: "The unthinkable has become possible. Who five years ago would have said the European Union could break up and disintegrate? Nobody!
"It was gratuitous to attack the European Union and its institutions because they were unbreakable."
The senior EU official put the migration crisis at the heart of the bloc's troubles.
He added: "The European Union is not unbreakable, something that is breakable is extremely valuable.
"What is the issue that has brought the European Union to the brink? The issue of migration.
"The issue of migration has played a key role in all of our member states, wherever we are.
"Only we, as a European Union, can convince our citizens that we do have an answer to this – not deny migration, not pretend you can solve it by building fences and walls, not pretending we can solve it by letting everybody in.
"If you understand that we need a comprehensive approach to the migration issue, and only at European level will this comprehensive approach be valuable and work. If we cannot convince our member states and citizens of that, then we will be in the same situation as the Dutch citizens were in 1581."
The EU has been threatening to tear itself apart over migration, with Italy, Spain, France and Brussels all at loggerheads over potential answers to a fresh crisis.
Nations are starting to rebel against Jean-Claude Juncker’s plans to include more funding for refugees in the EU’s next budget, mainly from Italy’s new coalition government of Lega and the Five Star Movement.
Tensions reached fever pitch when Matteo Salvini, Rome’s new interior minister and deputy prime minister, blocked a ship carrying 630 migrants, including seven pregnant women, stranded in the Mediterranean.
With Malta also refusing to accept the Aquarius vessel operated by the charities Medecins Sans Frontieres and Sos Mediterranee, Spain’s new prime minister Pedro Sanchez instructed port officials to welcome the ship into Valencia.
Hungary’s praise for Italy’s rejection of the stranded migrants comes as another sign of the EU’s growing division over how to handle a future immigration crisis like that of 2015.