David Cameron arrives in Brussels later with a warning for his European colleagues: the migration route in the western Mediterranean could be back on within weeks.
The 28 leaders of the EU are meeting in Brussels to talk - yet again - about the migrant crisis.
It's the third time in four weeks they have met to discuss it.
Germany's Angela Merkel will come here just days after her party was humiliated in local elections as German voters voiced their anger and demanded Germany's open door was slammed shut.
When EU leaders met shortly before those elections, the German Chancellor attempted to push through a deal which she hoped would calm her voters fears over the numbers of migrants.
It was hastily arranged and it is hastily coming apart.
The plan involved deporting migrants arriving on Greek shores back to Turkey.
For every migrant returned, the EU would take one Syrian migrant from Turkey.
In return, Turkey would get lots of EU aid money - billions of it - as well as an acceleration of the process to allow Turkish citizens visa-free travel in the border free (Schengen) area of the EU.
Since the deal was cobbled together, there has been a host of moral, legal and political objections.
And it may well unravel today.
But EU leaders will meet today in a desperate bid to have something - anything - to present to Turkey's Prime Minister Ahmet Davutoglu tomorrow.
But as the EU Council tries to plug one leak, David Cameron will warn his European counterparts that another leak is about to spring open.
Whilst Downing Street says he will be supportive of any plan aimed at 'breaking the business model' of the traffickers operating in Turkey (which includes the deployment of the Royal Navy's RFA Mount Bay in the Aegean Sea) the measures should not and cannot ignore the route from North Africa.
Mr Cameron fears the longer - and much more dangerous - crossing from Libya to southern Italy is about to begin once more.
Over the last year, the migrant crisis has shown it can and will consistently outpace the EU's panicked responses.
There is no suggestion this crisis summit will be any different from those which came before.