BERLIN, Nov 18 (Reuters) - Here are key quotes from a news conference in Berlin with British Prime Minister David Cameron and German Chancellor Angela Merkel:
"I believe that one can win back credibility when one uses the powers at one's disposal.
"The British demand that we use a large amount of firepower to win back credibility for the euro zone is right. But we have to take care that we don't pretend to have powers we don't have. Because the markets will figure out very quickly that this won't work."
"This press conference is the answer to the question raised by a major German newspaper.
"I mean that in all seriousness because Great Britain was always a motor for more competitiveness, for openness in research, for completing the Doha round. We weren't always able to push everything through. It's clear that we have a lot of work on that issue.
"But the common conviction about how Europe can be successful, how we can maintain our prosperity, these common convictions are clearly in the forefront.
"Naturally there are differences. But Europe can only prevail if all the strong countries of the European continent are represented. And if we have a bit of tolerance for the different views, that we always have the strength in Europe to build such bridges even if there are different opinions on some issue. All I can say is that whenever David and I worked together on a problem we found a solution."
"On a purely European level, no progress has been made. Therefore we must work where there is a common view that it should be done. We are united in saying a global financial transaction tax would be introduced by both countries immediately but we did not make any progress on having such a tax just in Europe."
"The danger, we've always believed, is driving transactions to jurisdictions where this wouldn't be applied, so a global tax is a good thing.
"In Britain we have a bank levy so we believe we are asking financial services to make a fair and proper contribution to paying down our deficit and debt."
"There is great excitement everywhere at the moment about whether we in Europe are really holding together. I can tell you very plainly. We are holding together, we have held together and we will hold together. Because we know that in a world of 7 billion people, Europe has no other chance.
"When one has lost credibility, and the euro zone has lost credibility, it must work step by step to regain this credibility, and then one must bring into effect those things which have been agreed."
"My German isn't that good, I think a 'bazooka' is a 'Superwaffe', am I right? The chancellor and I would agree that whatever you call this we need to take decisive action to help stabilise the euro zone and that has to consist of the things that we have spoken about: decisive action on Greece, a European Financial Stability Facility that is with detail and meaning and power and punch behind it, and also the recapitalisation of the banks.
"We also agree that a strong, successful and sustainable euro is in all our interests. We need this crisis to be resolved. Britain, like Germany, has a big national interest in the crisis being resolved."
"We need to take decisive action to help stabilise the euro zone. And that has to consist of the things that we have spoken about; decisive action on Greece, a European financial Stability Facility that is with detail and meaning and power and punch behind it and also the recapitalisation of the banks."
"I very much agree with what Angela has been saying, that a long-term solution to this problem also has to involve proper rules for fiscal discipline in European countries so that we can't create this mess again."