Defence Secretary Liam Fox used his speech at the Herzliya conference to warn against complacency in the face of the growing nuclear threat from Iran and urged more robust action from the international community.
Speaking on Monday on a panel of defence ministers convened by European Friends of Israel, Dr Fox said: "When talking about timescales I do not think it is prudent to assume we are at the most optimistic end of the spectrum."
He said he did not agree with the assessment of outgoing Israeli Defence Minister Meir Dagan that Iran would not have nuclear weapons before 2015. Last week Dr Fox told parliament that Iran could have the capacity by next year.
"If Iran gets nuclear weapons it will be a disaster," he said, adding that such a move could destroy hopes for peace in the Middle East and would mark the effective end of nuclear non-proliferation treaty as we know it.
He said Britain was pushing for tougher sanctions against Iran. "An Iranian nuclear capability will not be tolerated by the international community. And that means the international community needs to act as well as speak."
We will not tolerate a nuclear capable Iran
Dr Fox claimed he was the first serving British defence secretary to visit Israel in "decades" and used the opportunity to discuss the protests in neighbouring Egypt. "We have to ensure that there are building blocks for democracy across the Middle East. The things that give us a higher moral authority is something we cannot deny other nations," he said.
Relations between the UK and Israel have been helped by a converging position on Iran. Diplomatic wounds that had opened up over the threat to arrest senior Israeli politicians for war crimes have begun to heal since the announcement of new legislation on universal jurisdiction.
The Herzliya conference welcomed a large contingent of delegates from British politics. This included a significant group of Labour MPs who support Israel. Michael Dugher, the shadow defence minister and former spokesman for Gordon Brown, spoke on Tuesday on the subject of Israel and Europe. Former chair of Labour Friends of Israel Stephen Twigg, and former defence minister John Spellar were also present, as was Conservative MP Greg Hands.
The subject of delegitimisation was a constant theme and Britain's role at the centre of this movement was raised on several platforms. On Tuesday, the assault on Israel's legitimacy enjoyed its own session in the main auditorium with Israel's ambassador to the UK, Ron Prosor and Lorna Fitzsimons of BICOM, both on the panel.