EU politicians and pundits have been reacting to UK Prime Minister David Cameron's pledge of a referendum on EU membership if his party is returned to office in the next British general election.
There was concern that Mr Cameron was proposing a "28-speed Europe" and a suggestion the UK was trying to impose its own rules on the rest of the EU.
Angela Merkel, German chancellor
"Germany, and I personally, want Britain to be an important part and an active member of the European Union.
"We are prepared to talk about British wishes but we must always bear in mind that other countries have different wishes and we must find a fair compromise. We will talk intensively with Britain about its individual ideas but that has some time over the months ahead."
Guido Westerwelle, German foreign minister
"Germany wants the United Kingdom to remain an active and constructive part of the European Union...
"We strive to create a better Europe, the European Union becoming even stronger with overcoming the debt crisis and regaining global competitiveness. Germany wants an ambitious reform of the economic and monetary union. In such decisive issues as the future of the common currency, we do not need less, but more integration."
"We share the vision of a better Europe. We need a new commitment to the principle of subsidiarity. Not all and everything must be decided in Brussels and by Brussels. We do indeed differentiate but cherry-picking is not an option.
"We share a common destiny in challenging times of globalisation. And in challenging times of globalisation, we as Europeans, we are all in the same boat."
French President Francois Hollande's spokeswoman, Najat Vallaud-Belkacem
"The president of the republic has clearly shown his wish for the United Kingdom to remain within the European Union...
"[But] being a member of the European Union involves obligations."
Laurent Fabius, French foreign minister
"It could be dangerous for the UK itself because the UK outside Europe? Difficult. The other day I was at a meeting with lots of British people, in particular businessmen, and I told them cleverly that if the UK decides to leave Europe we will roll out the red carpet [to attract them].
"We want the British to be able to bring all their positive characteristics to Europe... but you can't do Europe a la carte. I'll take an example which our British friends will understand. Let's imagine Europe is a football club and you join, but once you're in it you can't say, 'Let's play rugby'."
Pierre Moscovici, French economy minister
"Great Britain is a peculiar member of the European Union, of course, and, from the start, it has asked for a cheque which still exists. It is not a party to the Schengen treaty, but at the same time, it is extremely useful."
Mario Monti, Italian prime minister
"I am confident that if there is to be a referendum, the UK citizens will decide to stay in the EU and contribute to shape its future."
Michael Spindelegger, Austrian foreign minister
"We do not like cherry-picking for one country. We think all 27 should take part in change, we want more Europe. The question of competiveness is important for all of us, for the jobs, the economy. This can only be successful if you pull together in the same direction."
Petr Necas, Czech prime minister
"We share the view with the United Kingdom that Europe should be more flexible, more open, should strive more for confidence among its citizens.
"We have no interest in Britain's departure from the EU, on the contrary, we have interest in a European future for the United Kingdom."
European Commission spokeswoman Pia Ahrenkilde Hansen
"[The European Commission] welcomes that David Cameron wants Britain to remain in the EU...
"[It] is very much in the EU's interest and UK's interest [that London remain] an active member."
Martin Schulz, speaker of the European Parliament
"We need a UK as a fully fledged member not harbouring in the port of Dover. UK can shape EU by working with its partners. Cameron's Europe a la carte not an option. We have to focus on jobs & growth rather than getting lost in treaties discussions...
"They [the UK] are the ones who are largely responsible for the delays in Europe and also the ones pointing their fingers at Europe."
"I have an impression that this speech was directed more at Tories than towards the European Union. A prime minister who says 'I will hold a referendum, but only after the next elections', is eyeing the next elections and not the referendum. I find what Mr Cameron is doing very implausible."
Franco Frattini, Former Italian foreign minister
"United Kingdom is an indissoluble part of the European Integration Process. I wish London will decide to remain in Europe."
Carl Bildt, Swedish foreign minister
"Flexibility sounds fine, but if you open up to a 28-speed Europe, at the end of the day there is no Europe at all. Just a mess."
Pekke Huhtaniemi, Finnish ambassador to the UK
"We all need to reflect on this speech. It could create anxiety and uncertainty around the EU. Other members will now need to think how to react. There will be tough negotiations ahead. Finland would never want Britain to leave the EU. Finland and Britain have been like-minded on trade so we'd lose an important ally."
Joschka Fischer, former German foreign minister, writing on the Sueddeutsche Zeitung website
"There are many reasons to believe that the referendum policy of the British Conservatives will trigger a dynamic which will now be difficult to control and which may even end in Britain's unintended exit from the EU. For the EU, Britain's exit would be a heavy blow, but for the British it would be a real disaster... The belief the EU could engage in new negotiations, and Germany could support this, borders on a belief in miracles."
Thomas Mayer, Europe editor at Austrian daily Der Standard
"After Cameron speech and Elysee celebrations it is clear that Europe needs German-French axis more than ever, UK cannot be relied upon, Tories have drifted off."
Mats Persson, director of Open Europe think tank
"Given that virtually all of the broad proposals mooted for more eurozone integration require some re-opening of the EU treaties at some stage, to which the UK must give its approval, Cameron will most likely get opportunities to negotiate a new deal.
"European partners who feared an imminent dawn raid on Brussels will be relieved. He has set out a plausible and powerful case for EU reform. For this, he should get a fair hearing in national capitals."
Nacho Torreblanca, columnist for Spain's El Pais newspaper
"Cameron corners himself. Will ask people to choose from two options he dislikes.
"Britain loves the single market and competitiveness but wants to dump on labour regulations. Contradiction.
"Cameron misses one key point: the 26 will decide for him. Why would they accept his terms.
"Why should fisheries be exempted from the single market? Just because Britain can't compete with others?"
Francois Beaudonnet, France 2 TV correspondent in Brussels
"Heard this in the corridors of the European Parliament - 'The British have sabotaged European construction and now they are abandoning us'."