IT IS almost the love that dare not speak its name. Ever since Azerbaijan's independence in 1991, relations between the Jewish state and a Shia Muslim one have grown and flourished. Both fear Iran; both have things the other wants. In a 2009 American diplomatic cable published by WikiLeaks, Ilham Aliev, the Azeri president, was quoted as saying that the relationship was like an iceberg: nine-tenths of it was “below the surface”.

What is known is that Israel gets a good third of its oil from Azerbaijan, via a pipeline that ends at Ceyhan in Turkey, whence it is shipped to Israel. An Azeri drilling company is hoping to strike big in Israeli waters just off the southern port of Ashkelon. Azerbaijan, now a member of the UN Security Council, generally votes with Arab and Muslim countries when it comes to resolutions on Israel. Israelis say they mind more about what Azerbaijan does than what it says.

In the past decade Azeri-Israeli trade has grown fast. But the figures do not spell out the size of one-off sales of Israeli military stuff, which make the statistics bounce around. In 2008 Azerbaijan's recorded exports to Israel (almost all oil) were officially worth $3.6 billion; in 2009 they were $1.2 billion; in 2010, $1.7 billion. The lower figures are unlikely to record the full extent of the trade.

One of Azerbaijan's largest mobile-telephone providers is a joint venture with an Israeli company. Now Israelis are coming in ever greater numbers to invest, some from industries such as defence. In March Israelis and Azeris, in a joint venture, began to produce drones.

Azerbaijan's leaders fear Islamist influence from Iran, where a quarter of the people are ethnic Azeris, whereas Iran's ayatollahs fear the influence of secular Azerbaijan. Iran has scolded Mr Aliev for his cosiness with Israel. Azeri officials are loth to discuss reports that Israel is helping train Azerbaijan's forces. Turkey, which is close to Azerbaijan, also resents Mr Aliev's warmth to Israel. But when Turkey's envoy to Baku, the Azeri capital, urged Azerbaijan's government to follow the Turkish lead in breaking relations with Israel, he got short shrift.