Will Boris regret his attack on Fallon?

Boris has been Boris again, to use the Prime Minister's indulgent phrase.

In the Commons yesterday, the foreign secretary harpooned the former defence secretary Sir Michael Fallon - and in the process he both broke the convention that ministers do not reveal cabinet conversations, and he traduced a Tory colleague.

I am told he has written a letter of apology to Sir Michael.

When Johnson took questions on President Trump's unilateral decision to pull out of the international deal to constrain Iran's future nuclear capability, the so called JCPOA, the former defence secretary Sir Michael Fallon said this:

Johnson's reply was sharp and dismissive: "I do not recall him making those points when he was serving so well as Secretary of State for Defence when the deal was done, and I disagree with him".

Fallon's friends were shocked by Johnson's statement. They say:

1) That Fallon has been critical of the limitations of the JCPOA for a considerable time;

2) That Johnson seems to have broken the convention that cabinet conversations are not aired in public;

3) That Johnson was not in the Cabinet when the JCPOA was agreed, so he could not know what Fallon said at the time;

4) You don't put down colleagues like that.

I am told Fallon - who resigned from the cabinet in November after conceding his previous conduct with women had not matched standards expected of the armed forces he represents - was pretty upset. And in the end Johnson conceded and has written a letter of apology.

But Johnson has done himself no favours among unaffiliated Tory MPs who might have considered voting for him in a future leadership election.

12.22 Addendum. Johnson’s aide is insisting his boss has not written Fallon a letter of apology, though they have spoken. I am somewhat astonished given what my sources told me. But there you are.

12.33. My bad, as they say. In fact Johnson wrote a text of apology to Fallon rather than a letter. And Johnson said he would tweet an apology, but he has not!