The six founding members of the EU have recommitted to building an “ever closer union”, but they have acknowledged differences with other states and for the first time they have backed a “two-speed” Europe.

At informal talks on Tuesday (9 February) in Rome, where the bloc’s founding treaty was signed in 1957, the foreign ministers of Belgium, France, Germany, Italy, Luxembourg and the Netherlands underscored that for them answers to the EU’s challenges lay in more integration, not less.

Student or retired? Then this plan is for you.

In a nod to Britain, they acknowledged that not every country should have to agree.

"We firmly believe that the European Union remains the best answer we have for today's challenges and allows for different paths of integration," their joint statement said.

"We remain resolved to continue the process of creating an ever closer union among the people of Europe.”

Solidarity under threat

London has demanded that the treaty commitment to pursue an “ever closer union” not apply to the UK, as part of British PM David Cameron’s set of proposals to be agreed next week at an EU summit before holding a referendum on its membership of the bloc.

While the “two-speed” EU has already become a reality, with 19 members using the euro and not all members participating in the passport-free Schengen area, officially enshrining the different pace at which member states integrate has been a political taboo for European elites.

At the low-key event, the foreign ministers acknowledged that the EU was facing "very challenging times" due to the migration crisis and the threat posed by terrorism.

They argued that Europe was “successful when we overcome narrow self-interest in the spirit of solidarity”.

That spirit of solidarity has been eroded somewhat by the euro debt crisis, where eurozone countries were asked to bail out each other, and with the migration crisis in which member states that have taken in most of the asylum seekers have asked others, in vain, to share the burden.

The crises have shaken both the euro and the Schengen zone.

EU's 'hardest moment'

The UK’s demands also reinforced the notion that some member states want less from the EU, not more.

London’s request to drop the commitment to political union and boost safeguards for non-eurozone members while reinforcing the single market has found support from eastern member states including Hungary and Poland.

After the meeting, Italian foreign minister Paolo Gentiloni said: “Without any doubt, Europe is going through one of its hardest moments since its foundation around 60 years ago.”

Tuesday's talks were called by Italy, whose centre-left government wants the core EU countries to go ahead with further integration.

The foreign ministers also pledged to fight terrorism and racism, and safeguard common values.

“More must be done to prevent radicalisation and develop a counter-narrative,” their statement said.

“This also means fighting the enemies of our fundamental values. We confirmed the need to further reinforce action against terrorist threats, in full compliance with human rights and the rule of law.”