Leading article: This cruel and ineffective blockade of Gaza must be brought to an end

Israel's brutal assault on the international aid flotilla bound for the Gaza Strip has united the outside world in agreement on one thing. The US Secretary of State, Hillary Clinton, and the Quartet's Middle East peace envoy, Tony Blair (not to mention our own Prime Minister), have demanded an end to Israel's economic blockade of Gaza, which this naval convoy set out with the intention of challenging.

Such pressure comes appallingly late in the day. For three years, this siege has been a form of collective punishment on the 1.5 million Palestinians of Gaza. And it is scandalous that it has taken the deaths of nine passengers on the aid convoy this week for Israel's conduct to come in for serious international criticism.

The cruelty of the blockade is obvious. Israel claims that it allows in all the humanitarian aid that Gaza needs. But the United Nations says that less than a third of the necessary supplies get through. The result for Gazans is widespread malnourishment. The embargo on fuel has created chronic shortages of electricity. The blockade on construction materials means that three-quarters of the homes and buildings destroyed in the 2008/2009 Israeli invasion have not been rebuilt. Gaza's sanitation system is close to collapse.

The human cost of this economic strangulation can be seen in the plight of five-year-old Taysir Alburai, whose story we report today. Some Israeli officials joked about "putting the Gazans on a diet" when they first imposed this blockade. In the struggles of Taysir and his family we see the terrible consequences of this policy.

The Israeli government argues that moral responsibility for the privations of the Gazan population lies with Hamas, which refuses to renounce its commitment to the destruction of the state of Israel. The siege could be lifted tomorrow, they claim, if Hamas would only renounce violence.

Leave aside that Hamas has said that it is willing to enter into a long-term truce with Israel and consider the fact that the blockade is strengthening, rather than weakening, the militant group. Hamas's control of the smuggling tunnels into Egypt – the strip's economic lifeline – has reinforced its power. Virtually all other private enterprise has been crushed. And, with weapons being brought in through those tunnels, the blockade is not even succeeding in disarming Hamas. Israel's blockade is not only cruel; it is ineffective.

Yet the Israeli government seems unable to admit that its policy is failing. Vocal elements of Israeli public opinion are pushing for a still tighter squeeze on Gaza. Israel is a country which has ceased to listen to the voice of even its firmest allies in the outside world.

International intervention is needed to break the deadlock. If Israel will not lift the blockade, then a United Nations aid flotilla should be sent. The Israeli military might feel no compunction about boarding private vessels, but a UN convoy would be a different prospect. Meanwhile, the US must put pressure on Egypt to open Gaza's southern border. Cairo has opened the Rafah crossing in the wake of this week's flotilla deaths. But this is likely to be only a temporary measure.

The Gazan people need more than short-term relief. They must be allowed to breathe freely again. And the international community has a moral responsibility to ensure that this freedom is granted.