The UK foreign secretary, David Cameron, has urged Israel to act with its head as well as its heart and not escalate the conflict by mounting a revenge raid on Iran. His remarks imply the UK would not take part in an attack on Iran but would continue to defend Israel if it came under further assault. Lord Cameron said: “We are saying Israel has a right to respond but we do not support a retaliatory strike. There are times where we have to be smart as well as tough, where we have to use head as well as heart.” He said Israel had a right to respond but suggested the hostilities at the weekend had been a double defeat for Tehran. “Not only was their attack an almost total failure but also the rest of the world can now see what a malign influence they are in the region and understand their true nature.” In one of a series of interviews, he said on Sky News the UK would have responded if a UK diplomatic facility had been attacked by missiles – but he condemned the scale of the Iranian response to the attack on its consulate in Damascus involving drones, cruise and ballistic and missiles, saying: “If those weapons got through it could have led to thousands of civilian casualties.” Pressed on LBC on the wisdom of the Israeli embassy attack in Damascus, the former Conservative prime minister said: “It is a matter for Israel. We have not made a comment on it. Can I understand Israel’s frustration with Iran? Yes. Absolutely I can. I am not getting into what Israel has or has not done.” He said: “Iran is responsible for Hamas in Gaza, they are responsible for what is happening in Yemen, they are responsible for Hezbollah in Lebanon.” Cameron said Israel should, as President Joe Biden had said to them, “take the win and then move on to focus on how to eradicate Hamas in Gaza and how to get those hostages free”. He added: “Israeli people this morning are thinking ‘We’ve suffered this massive attack. Of course, we want our government to respond.’ And that’s why I think we have to be sensitive in the way we put this, but to say ‘Look, you have had a win because the Iran attack was such a failure and the smart thing to do as well as the tough thing to do now is actually not to escalate.’” The Iranian attack, which reportedly included 110 ballistic missiles, 36 cruise missiles and 185 drones, was much larger than the Iran foreign minister had assured him it would be, Cameron said. Calling for a pivot to Hamas and the hostage talks, he said: “Hamas have been offered a deal by Israel to release many, many prisoners inside Israeli prisons and to have a pause in the fighting in Gaza, and Hamas should take that deal. They are the only reason why there’s fighting continuing.” Cameron predicted a significant change in the way Israel was handling the aid issue. “We have now seen Israel saying, ‘We’re going to allow more aid into Gaza, 500 trucks a day, opening the port of Ashdod, opening times lasting longer and proper deconfliction’.” But he said: “It has been immensely frustrating. But we are now making progress. And I’m checking daily that whether the things Israel has said the a’re going to do they will actually do,” adding that he would continue to press Israel on the issue. Cameron also defended UK arms sales to Israel, saying the attacks at the weekend had shown how important it was that Israel was able to defend itself. “What Saturday night in many ways proves is that Israel does need the right to defend itself, and indeed the means to do so. Had these weapons got through, we could have seen thousands of people killed, including citizens of Israel, and a very significant escalation in this conflict.”