Bahrain and other members of the Gulf Cooperation Council (GCC) are in negotiations to buy the Israeli-developed Iron Dome anti-missile system to defend against "a growing arsenal of Iranian missiles".
The Israeli weapon, which has reduced the effectiveness of rockets fired out of Gaza into Israel by about 90% would be bought through Raytheon and other American contractors who developed the Iron Dome with Israeli arms giant Rafael.
A deal for the whole of the GCC, which includes Saudi Arabia and the United Arab Emirates, Oman, Qatar and Kuwait, would be worth tens, perhaps hundreds, of billions of dollars.
It would also include longer range interceptor missiles such as David's Sling, and the Arrow I and Arrow II which are capable of intercepting supersonic intercontinental ballistic missiles - also a joint venture between Israel and the US.
Khalid bin Mohammed al Khalifa, Bahrain's foreign minister said on the visit to London: "The Israelis have their small Iron Dome. We'll have a much bigger one in the GCC."
The sale of Israeli-developed weapons to a Gulf state, or states, would have been controversial for both the Israelis and the buyers a few years ago.
But both now see one of the main threats to them as the growing military strength and ambitions of Iran.
The US is quietly playing the "middle man" in the deal as a sweetener to bitterness caused in the Gulf over what the leadership in that region believe is a "naive" deal with Iran over its nuclear weapons programme.
"Iran has been trying to undermine and topple government in our region for years," the Bahrain foreign minister said.
He said that Iran's precision missile capacity was certain to increase as a consequence of the lifting of sanctions following the internationally brokered agreement with Tehran to end its nuclear weapons development.
"They will put a lot of money into this programme to develop techniques and tactics to defeat our missile defences ... the strategy appears to be one of saturation to stockpile enough missiles to overwhelm any defence system we build in the Gulf," he added.
As a result of this perceived threat, plans to buy Israeli weapons, via the US, would result in a profits bonanza for both American and Israeli firms.
Talks are understood to be well advanced.
One senior Gulf government source said: "If Netanyahu were not making less of a mess of things and was more like Anwar Sadat (who signed a peace deal for Egypt with Israel) then we would be happy to buy the missiles straight from Israel."
Israel developed its anti-missile systems to defend against Gaza's rockets in part but overwhelmingly against Hezbollah's arsenal in southern Lebanon.
Israeli sources claim that this includes weapons capable of precision attacks on any target inside the Jewish State as well as up to 100,000 other missiles of less capability and accuracy which have been accumulated to try to overwhelm the Iron Dome and other systems with Iranian funds and supplies.
Led by Saudi Arabia, GCC nations are locked in a bloody conflict with Shi'a Houthi rebels in the Yemen which western and Gulf intelligence sources insist are backed by Tehran.
The GCC's fears of an Iranian threat increasing when sanctions are lifted has been further deepened by Tehran's growing alliance with Moscow which, like Iran, has come to the military defence of the government of Bashar al Assad in Syria.
As a Shi'a-Russian crescent of influence is seen spreading across the Middle East so Gulf States have been privately reaching out to the old enemy to Israel.
Now with a potentially massive arms sale, those relations are begin to emerge from the shadows of regional rivalries.