The normally secretive ties between Israel and Saudi Arabia are coming out of the closet as both countries gear up to confront joint regional challenges and lobby against the impending P5+1 nuclear deal between the international community and Iran.

Last week at a conference in Washington held by the Council for Foreign Relations, Dore Gold, the incoming director-general of the Israeli Ministry for Foreign Affairs, and Anwar Eshki, a retired Saudi general who acted as a senior adviser to the country's leadership, shared a stage and spoke of the two countries' common enemy - Iran.

Such a public engagement would have been unthinkable only a few months ago.

Mr Gold, a former Israeli UN envoy and Prime Minister Benjamin Netanyahu's diplomatic adviser, said: "Standing today on this stage doesn't mean we have resolved all our differences," but stressed: "Our hope is we will be able to address them in the years ahead."

General Eshki emphasised that both countries saw Iran as the main threat to regional stability but added that official diplomatic relations between Israel and Saudi Arabia would only be possible when Israel agrees to the Arab Peace Initiative. The plan requires an Israeli withdrawal from all territories captured in the 1967 Six-Day War and entails the establishment of full diplomatic relations with the Arab nations.

Saudi Arabia and Israel are also part of a regional coalition, including Egypt, which is trying to crack down on groups such as the Muslim Brotherhood and Islamic State (IS). Another member of this group is Jordan, which has recently muted its criticism of Israel.

There has also been a change in the public perception of Israel in Saudi Arabia. The Inter-Disciplinary Centre in Herzliya conducted a phone poll among Saudi civilians that was published last week. According to the results, 53 per cent of Saudis saw Iran as their biggest enemy, followed by 22 per cent pointing to IS. Only 18 per cent said Israel was their main enemy.