But Hungary objects to being considered a “frontline” state in this crisis, and may simply not participate. The Czech Republic is among those EU states opposed to the obligatory quotas mandated by the European Commission, insisting instead on a voluntary approach.
Mr Cameron has said they will come from refugee camps in countries neighbouring Syria such as Lebanon and Jordan.
Why are European Union governments arguing over it?
The migrants do not want to live in those countries either, meaning that the feasibility of the plan was in serious doubt before Slovakia’s bombshell intervention.
Slovakia and Hungary reacted furiously to the relocation vote.
That figure is dwarfed by 1mn asylum seekers that Germany is expecting to welcome by the end of this year.
US President Barack Obama has pressed European nations to take their “fair share” of refugees.
But tensions have kept boiling over, with fears the EU’s cherished Schengen passport-free zone could be under threat from the tide of migrants, many of whom are trying to make their way to Germany.
The BBC’s Europe correspondent Chris Morris says it is highly unusual for an issue like this – which involves national sovereignty – to be decided by majority vote rather than unanimous decision.
It was tonight unclear whether or not Brussels would be able to force any country to take in its required quota of migrants whilst the legality of the scheme remains in doubt.
Ireland did not have a vote, as it has an automatic opt-out on justice matters.
The migrant invasion could very well destroy the EU.
Would voluntary relocation actually work?
For all the controversy, Tuesday’s plan would find homes for just 20 days’ worth of new arrivals to Europe, a measure of the scale of the crisis and the baby steps the continent has taken to address it. Croatia said Wednesday that more than 44,000 migrants had entered its territory in the last week alone.
The figure of a further 120,000 is dwarfed by the size of the problem.
Roughly 500,000 people from the Mideast and Africa this year have fled to Europe.
Some 5,000 people daily pass through Idomeni on the Balkans route towards prosperous western European economies, more than double the numbers a few weeks ago, police said.
“The Secretary-General is extremely concerned about the deteriorating situation facing refugees and migrants arriving across Europe”. Sweden and the United Kingdom are also popular destinations.
Prime Minister Viktor Orban was in Vienna on Friday meeting with Austrian Chancellor Werner Faymann and other officials to discuss the migration crisis.
He said: “We urge the UK Government to commit the resources necessary for the implementation of the resettlement programmes for the short and long term, beyond the period for which funding is guaranteed to local authorities“. That certainly doesn’t seem like solidarity among the European Union countries.