This is what the prime minister’s spokeswoman said when asked if David Cameron was worried about Gen Sir Nicholas Houghton, the chief of the defence staff, getting involved in party politics by criticising Jeremy Corbyn’s views on nuclear weapons. She said:

The chief of the armed forces was talking to Andrew Marr. He made a point about the credibility of deterrence. He was clear that he was not talking about a personal thing.

At this point a report made the point that criticising Corbyn did seem pretty personal. The spokeswoman went on:

He was asked about deterrence. He made the point about the credibility of the deterrent.

As the principal military adviser to the government, it is reasonable for the chief of the defence staff to talk about how you retain the credibility of one of the most important weapons in your armoury.

• No 10 says head of the armed forces was entitled to criticise Corbyn’s views on nuclear weapons because he’s the “principal military adviser to the government”.

Tomorrow David Cameron is going to publish the letter he is writing to Donald Tusk, president of the European Council, setting out Britain’s demands in the EU negotiation. Today we learn that Tusk should not expect a letter because Cameron will be able to fit it all in on the back of a postcard. He has boiled it down to one word.

In news terms, there is not much surprise in what that word is (“flexibility”). What was interesting about the speech was not so much the content, which was not particularly novel, but the presentation. As he focuses increasingly on the renegotiation, and the forthcoming EU referendum, Cameron is finessing his argument, and boiling it down to some voter-friendly messages. The Telegraph’s Ben Riley-Smith points out two of them.

Here are the key points.

• Cameron said he had no “emotional attachment” to the EU institutions. He was just interested in what was right for Britain, he said.

I don’t have any emotional attachment to the institutions of the European Union. But I have a very strong emotional and practical attachment to asking the simple questions for Britain: How do we have more influence in the world? How do we have more prosperity? How do we have more jobs? How do we do the best for this country we love? For me, that’s what it’s all about.

• He said his EU renegotiation demands could be summed up in one word: flexibility.

In a way you can boil down all of my renegotiation to one word: flexibility. Is this organisation flexible enough to make sure that that countries inside the eurozone can grow and succeed, and countries outside the eurozone, like Britain, can find what they need as well? If it’s flexible enough, we’ll stay. If it’s not flexible enough, we have to ask ourselves a very profound question: Is this organisation for us?

He also said, at another point, that he wanted a “live and let live” Europe.

• He said that he was not starting the referendum campaign now, but that he did want to confront some “duff” arguments about the EU. One of these was the claim that Britain would be better off like Norway, outside the EU but with access to the single market. In fact, this would mean Britain being subject to regulations it could not control, he said.

• He said another “duff” argument was that Britain could not survive outside the EU.

Today I want to debunk an argument that is sometime put around by those who say, ‘Stay in Europe, come what may’. Some people seem to say that really Britain couldn’t survive, couldn’t do okay outside the European Union. I don’t think that’s true. Let’s be frank, Britain is an amazing country. We’ve got the fifth biggest economy in the word ... The argument isn’t whether Britain could survive outside the EU. Of course it could.

• He insisted that he was serious about leaving the EU if he did not get what he wanted in the renegotiation. Patience should not be confused for lack of resolve, he said.

Patiently setting out a list of very sensible changes shouldn’t be mistaken for a lack of resolve. If these things can’t be fixed, then Britain would naturally ask: Do we belong in this organisation?

• He claimed he was still committed to stopping EU migrants claiming benefits for four years. But, when asked about this, he left out the point about “four years” in his reply, suggesting he may be reconciled to some form of compromise on this. (See 10.13am.) This is what he said in response to the question from the BBC.

On the migrant issue, we have not changed our view at all. We believe that what is set out in the manifesto is right for Britain, right for Europe and needs to change.

• He said he wanted Britain to have mega tech companies like Google or Facebook.

Q: What can be done to promote tech start-ups in the UK?

Cameron says Britain is doing better than other European countries are creating a pro-tech, pro-entrepreneur market. There is a real buzz in this sector in Britain.

But Britain has not had mega-businesses, like Google or Facebook. We need that kind of ambition.

• Cameron says Britain needs companies like Google or Facebook.

One thing the government is doing is encouraging coding in schools.

And the planning system is more flexible.

But the government would like to hear ideas about what could be done, he says.

He says he met the head of Lego recently. The Lego boss said the firm was setting up in the UK because it was the best place in Europe for technology.

Q: Your EU plans will require treaty change. Some countries will have to vote on those. How can you be confident countries like Ireland, for example, will vote for these measures?

Cameron says his plans will require treaty change.

He wants an assurance that the changes are “legally binding and irreversible”.

But he is confident he can do this.

That’s because other countries want changes too, for example on “ever closer union”.

He wants a “live and let live” Europe.

Cameron is now taking questions.

Q: How can you succeed in a negotiation when everyone thinks you are bluffing? People think you want to stay in the EU whatever happens.

Cameron says he could not have been more clear with EU colleagues. He has seen very president and prime minister and patiently said what needs to change.

But patience should not be confused for lack of resolve.

If these problems cannot be fixed, what is the point of saying.

His demands can be boiled down to one word: flexibility.

He wants to ensure that the EU is flexible enough.

Q: Are you still committed to stopping EU migrants claiming benefits for four years after they arrive?

Cameron says what was set out in the Conservative manifesto has not changed.

In his answer, Cameron does not mention the four-year timetable.

Q: Given the trouble you have over tax credits, how can we be sure you have the stomach for another round of austerity?

Cameron says the government has to make sure the economy is safe and secure.

Cameron says another argument he wants to “debunk” is the one that Britain could not survive outside the EU.

Britain could survive outside the EU, he says. It has the fifth largest economy.

The argument is not about whether Britain could survive outside the EU. It is about whether or not it would be better off outside the EU.

He goes on:

I don’t have any emotional attachment to the institutions of the European Union.

But he is firmly committed to Britain, and what’s best for Britain. The referendum will be about what’s best for Britain.

David Cameron is speaking to the CBI now.

He starts by welcoming the fact that a woman, Carolyn Fairbairn, is becoming the new head of the CBI.

He says this has been a good period for enterprise. Britain has four of the 10 “unicorns” in Europe, he says, referring to start-ups now worth $1bn.

Cameron says his speech will specifically talk about Europe and the deficit.

Here are some Twitter highlights from George Osborne’s speech.

• Osborne says prison system is a “shocking example of state failure”.

Michael Gove, the justice secretary, said this morning that one of the problems with Victorian prisons is that they contain “the dark corners which too often facilitate violence and drug-taking”.

But Frances Crook, head of the Howard League for Penal Reform, says he’s wrong.

In a recent blog about Gove’s speech to the Howard League (which left her “blown away”, she said, because of his commitment to rehabilitation), Crook said closing old prisons and replacing them with new ones was a bad idea.

[Gove] re-floated the idea of closing Victorian prisons and building airy new prisons. I think this is a non-starter.

Firstly, it is not clear who owns the land on which the Victorian prisons sit and you can’t sell what you don’t own.

Secondly, it is not that the Victorian prisons are badly designed, they are just overcrowded. Oxford prison has been turned into a very swanky hotel so it is possible to make the buildings sanitary and functional and they are anyway quite beautiful. So the problem is not the buildings, it is the overcrowding.

Thirdly, which egg will come first? If he closes the Victorian prisons and reduces prison numbers what is the point of building expensive new prisons that will just encourage the courts to use them. If he builds new prisons before closing the Victorian jails, the new ones will fill up and then he will have both new and old.

I was encouraged that the Secretary of State responded to a question from the audience about reducing prison numbers positively. That is the way forward. It is sensible, it is safe and it is cost-effective.

This morning Crook has been using Twitter to develop this argument.

Here are more quotes from the Treasury news release about the prison building announcement.

From George Osborne

This spending review is about reform as much as it is about making savings.

One important step will be to modernise the prison estate. So many of our jails are relics from Victorian times on prime real estate in our inner cities.

So we are going to reform the infrastructure of our prison system, building new institutions which are modern, suitable and rehabilitative. And we will close old, outdated prisons in city centres, and sell the sites to build thousands of much-needed new homes.

This will save money, reform an outdated public service and create opportunity by boosting construction jobs and offering more people homes to buy.

From Michael Gove, the justice secretary

This investment will mean we can replace ageing and ineffective Victorian prisons with new facilities fit for the modern world.

We will be able to design out the dark corners which too often facilitate violence and drug-taking.

And we will be able to build a prison estate which allows prisoners to be rehabilitated, so they turn away from crime.

It is only through better rehabilitation that we will reduce reoffending, cut crime and make our streets safer.

Gove is keen to show that he is deeply serious about prison reform. As I reported on the blog on Thursday, he got rave reviews at the Howard League for Penal Reform when he spoke to them last week about his commitment to improving rehabilitation and cutting the number of people in jail.