Quiet planning by the US, UK and other allies to help Israel repel an Iranian long-range attack have been going on for several months or more – but most of the defensive effort appears to have been undertaken by Israeli air defence systems. The only reported military engagements in support of Israel were a dozen interceptors fired by two US warships in the eastern Mediterranean, while Jordan said its own air defence systems and air force were involved in targeting Iranian missiles. Because the Iranian attack on Tuesday comprised 181 high-speed ballistic missiles, there was no role for US or UK jets. They had been on standby in the eastern Mediterranean to shoot down slower moving Shahed drones – as they had done during Iran’s previous attack in April, when a mixture of weapons were used. John Healey, the UK defence secretary, said two RAF Typhoons took off from RAF Akrotiri in Cyprus on Tuesday, but while they were “ready to engage” he acknowledged there was nothing for them to attack. “The nature of the attack was different,” the minister said. The US, which reported it was moving three additional air squadrons into the region on Monday, said its fighter jets had not targeted any Iranian missiles, though Pentagon officials were coy whether any had been used in aerial reconnaissance. Both countries maintain a standing air presence in and around the Middle East – and strengthened it in August, when it was feared Iran would respond militarily to the assassination of Hamas’s political leader, Ismail Haniyeh, in Tehran. The US sent the USS Abraham Lincoln carrier strike group of warships and fighter jets. Overt US military intervention was limited to the USS Bulkeley and USS Cole firing off a dozen interceptors, though it was not immediately clear if they were successful, the Pentagon said. Nor would the US confirm which missiles had been deployed, though SM-3 ballistic interceptors have been costed at $10m (£7.5) to $28m each. Interceptor missiles are more expensive than the missiles they seek to destroy, and in April US navy secretary, Carlos Del Toro, told the US senate that his force had spent $1bn on munitions, used to defend Israel in April and on attacking the Houthi rebels in Yemen who had been targeting commercial shipping. The cost of the interceptors is a key reason why fighter jets are used to target drones, ideally shooting them down with simple gunfire. But Iran’s goal, as well as to cause damage to Israeli airfields and other targets, was to inflict financial costs on the country and its western backers for helping it. Jordan, a western ally and recipient of over $1bn a year in US military aid, was involved again, as it had been in April, though the success of its efforts was also unclear. The country’s public security directorate said on Tuesday the air force and air defence systems “responded to a number of missiles and drones that entered Jordanian airspace”, though its report of drones appears inaccurate. Where US and other western support to Israel may have been more significant is in the area of intelligence. Although Iran said it passed on a warning about its attack via the Swiss embassy in Tehran, the foreign minister, Abbas Araghchi, said officials only did so, after missiles with 12-minute journey times had been launched. Given the US was warning of an impending attack around two and a half hours in advance, it is likely that this was derived from satellite or signals intelligence or both, which may have come from American, British, Israeli or other international monitoring – and most likely a combination of all to produce a coordinated picture.