ON the face of it, the historic deal reached by world leaders to limit Iran's nuclear activity in return for international economic sanctions being lifted is a cause for celebration.

Barack Obama has declared that the agreement would make the world "safer and more secure" while his Iranian counterpart, Hassan Rouhani, said it opened a "new chapter" in Iran's relations with the world.

That is all good to hear but, when it comes to the Middle East, it is never that simple. The Republican Speaker of the US House of Representatives, John Boehner, said the dropping of sanctions would "embolden" Tehran. Israel's Prime Minister, Benjamin Netanyahu, went further by describing the deal as a "stunning historic mistake" which is likely to fuel a nuclear arms race around the world.

Time will tell, of course, but it would be naive to believe that the agreement suddenly means that Iran has gone from pariah to trusted friend. Trust takes time to establish and the easing of sanctions must be gradual, in the full understanding that they can be swiftly restored if the agreement is broken.

Such are the tensions surrounding the region that anything could yet happen. It may prove to be the historic step towards greater world security that President Obama and David Cameron believe it to be. Or history may end up viewing it as the great error of judgement perceived by Israel.

It is a fine balance but it is surely a step worth taking. Ultimately, it has to be better to be talking than allowing bitterness to fester in silence.

It is an achievement to bring Iran into the fold – the bigger challenge is to maintain the dialogue and slowly build a trust based on solid evidence of peaceful intent.