LONDON (Reuters) - Prime Minister David Cameron gave more details of his plans to change Britain's ties with the European Union ahead of an in-out referendum he has said he will hold before the end of 2017.

Here are some of the highlights of Cameron's speech and a subsequent question-and-answer session with reporters on Tuesday:

ON THE RELATIONSHIP BETWEEN MEMBER STATES AND THE EU

"Never forget that the European Union now comprises 28 ancient nations of Europe. That very diversity is Europe's greatest strength. Britain says let's celebrate that fact, let's acknowledge that the answer to every problem is not always more Europe. Sometimes it's less Europe."

ON THE EU'S SINGLE MARKET AND COMPETITIVENESS

"We need to bring together all the different proposals, promises and agreements -- on the single market, on trade, on cutting regulation -- bring it all together into one clear commitment that writes competitiveness into the DNA of the whole European Union."

ON UK'S CONCERNS ABOUT 'EVER CLOSER UNION'

"I can tell you today that as part of our renegotiation, I'm asking European leaders for a clear, legally binding and irreversible agreement to end Britain's obligation to work for an ever closer union."

ON THE ABILITY TO BLOCK EU LEGISLATION

"We're not suggesting a veto for every single national parliament. We acknowledge that in a Europe of 28 (countries), that would mean gridlock. But we want to see a new arrangement where groups of national parliaments come together and reject European laws which are not in their national interest."

ON BRITAIN'S PUSH FOR CHANGE

"We gain from the union but we bring a lot to it. And we believe very strongly that if a major member state has major concerns, concerns which it has been voicing in a measured and constructive fashion over a number of years, then it is entitled to expect those concerns to be addressed.

"And at the heart of this negotiation is actually a very simple question: is the European Union flexible enough to accommodate the concerns of its very different member states. The answer to that question must be yes if the EU is to survive and prosper in the future."

ON NO SECOND REFERENDUM

"If we vote to leave, then we will leave. There will not be another renegotiation and another referendum. So I say to my European counterparts with whom I am negotiating, this is our only chance to get this right - for Britain and for the whole European Union."

ON THE TIMING OF THE REFERENDUM

"Am I in a hurry? Well, I want to get on with it. Since the election, I've been patiently meeting with European leaders across the continent. But as well as patient, and as well as wanting to get on with it, I will be persistent.

"I hope we can make really good progress in December and I've done everything possible to make that happen. We don't have to hold our referendum until the end of 2017, but I'm keen to secure these changes to get on with it, and I've been working very hard to do that."

ON SECURITY

"Today as we confront fresh threats and dangers to our country, I am in no doubt that for Britain, the European question is not just about economic security but national security too."