"All things must pass, all things must pass away. Sunset doesn't last all evening. A mind can blow those clouds away. Now the darkness only stays the nighttime; in the morning it will fade away. It's not always going to be this grey; all things must pass, all things must pass away." - George HarrisonAll Things Must Pass - A George Harrison Tribute
In an interview with Haaretz , Cohen stated, "There was a secret even before there was anything to hide. Some students were sent overseas to study nuclear physics, and a group started to look for uranium in the Negev. There was none. Nonetheless, this small group, which merely had a vision, already maintained a cult of secrecy. In those years, there was not yet an international regime against nuclear proliferation - this was a decade before the nuclear Non-Proliferation Treaty. But even then, when theoretically anything was allowed, there was a sense of taboo. That the subject could not be discussed. David Ben-Gurion and Shimon Peres understood that in this sphere you don't really want to state your objectives precisely. The sense was that designating goals would, in itself, stir an argument, and that it was better to avoid such debates, both internal and external. The idea was that it was crucial not to raise these questions. I read materials that are kept in archives around the world or are in memoirs. In particular, I carried out a large number of interviews and conversations with people. In my opinion, I have not written anything that harms the State of Israel; perhaps some things will help it." 
An American academic, Sasha Polakow-Suransky, also researched archives and memoirs and wrote in The Unspoken Alliance: Israel's secret alliance with Apartheid South Africa that Israeli officials "formally offered to sell South Africa some of the nuclear-capable Jericho missiles in its arsenal" and that PW Botha, South Africa's defense minister asked Shimon Peres-who was then Israel's defense minister-for nuclear warheads.
Peres offered them "in three sizes" which are understood as conventional, chemical and nuclear weapons.
The two signed a broad-ranging agreement governing military ties between the two countries that included a clause declaring that "the very existence of this agreement" was to remain secret.
On 4 June 1975, Peres and Botha met in Zurich and by then, the Jericho project had been renamed Chalet. The top-secret minutes of that meeting recorded that:
"Minister Botha expressed interest in a limited number of units of Chalet subject to the correct payload being available"Minister Peres said the correct payload was available in three sizes. Minister Botha expressed his appreciation." 
Botha did not go ahead with the deal because of the cost and the fact that final approval was dependent on Israel's prime minister. South Africa did build its own nuclear bombs and also provided much of the yellowcake uranium that Israel required to develop its nuclear arsenal.
The documents confirm also that former South African naval commander, Dieter Gerhardt admitted there was an agreement between Israel and South Africa called "Chalet" that involved an offer by the Jewish state to arm eight Jericho missiles with "special warheads" understood as atomic bombs.
"Some weeks before Peres made his offer of nuclear warheads to Botha, the two defence ministers signed a covert agreement governing the military alliance known as Secment. It was so secret that it included a denial of its own existence: 'It is hereby expressly agreed that the very existence of this agreement... shall be secret and shall not be disclosed by either party.'" [Ibid]
The secret military agreement signed by Shimon Peres, then president of Israel, and P W Botha of South Africa. Photograph: Copyright Guardian
Haaretz also reported that, "From 1963 onward, Ben-Gurion and Peres directed [Israel's nuclear weapons] project under a thick cloud of secrecy, Cohen says. Even senior figures involved in it did not know whether Israel was in fact determined to attain nuclear weapons, or whether it wanted to simply move closer to that watershed. Cohen's book includes a historic anecdote that shows how even at crucial phases in the project's development, Israel's decision-makers refrained from specifying, even in their own internal discussions, its genuine objectives.