Looking at the picture of EU foreign minister Cathy Ashton standing between representatives of the Iranian and American governments in Geneva late on Saturday night, it is easy to let the word “appeasement” slip from the lips.

The Israeli Prime Minister Benjamin Netanyahu wasted no time in calling the nuclear deal a “grievous historic error” — and he may well be right. UK Foreign Secretary, William Hague countered by saying: “We would discourage anybody in the world, including Israel, from taking any steps that would undermine this agreement and we will make that very clear to all concerned.”

It is unlikely Mr Netanyahu will be in any mood to take lessons from the UK government, which has been largely irrelevant in this process as it continues its retreat from frontline diplomacy in the Middle East.

It is no surprise to see opposition politicians taking credit for the involvement of Labour peer Baroness Ashton. At this stage, the interim agreement looks for all the world like a personal triumph for her. We shall see.

It is easy for the rest of the world to preach reconciliation while Israelis experience the existing conflict on a daily basis. Iran, via its proxies, is a very real presence on Israel’s borders and Iranian-made Grad missiles are regularly fired from Gaza.

The reaction of the Israeli press has been interesting. Even those who share Mr Netanyahu’s scepticism have urged him to tone down his language, which has sounded bitter and resentful. The Israeli prime minister has made halting the Iranian nuclear programme the focus of his premiership and now finds himself seriously outmanoeuvred.

Writing in Ha’aretz, Chemi Shalev put it well when he said: “So the question isn’t whether Israel is right, but whether it’s smart as well. Do insults, aspersions, accusations and complaints advance or harm the country’s national interests? Is perpetual petulance and in-your-face bellyaching really a constructive form of diplomacy?”

British supporters of Israel would do well to heed this advice before rushing to use the “A-word”.

This does not mean we should rush to welcome Iran in from the cold. I was struck by the contrast between the hugs given to the noble Baroness by the American team and the lack of any physical contact from the Iranian negotiators. Beyond this symbolic and ignoble misogyny lies all the daily horror of Iran: the public executions, the persecution of gays and minorities, the crushing of dissent, the systematic torture, the funding of international terror.

And yet, it should be possible to stare the reality of the Iranian regime in the face and still recognise the small possibility that the deal brokered last weekend could be a genuine breakthrough.