If an 85-year-old Holocaust survivor had gone on hunger strike in support of a besieged people in another part of the world, and hundreds of mostly western protesters had been stoned and beaten by police, you can be sure we'd have heard all about it. But because that is what's been happening in western-backed Egypt, rather than Iran, and the people the protesters are supporting are the Palestinians of Gaza instead of, say, Tibetans, most people in Europe and north America know nothing about it.

For the last fortnight, two groups of hundreds of activists have been battling with Egyptian police and officials to cross into the Gaza Strip to show solidarity with the blockaded population on the first anniversary of Israel's devastating onslaught. Last night, George Galloway's Viva Palestina 500-strong convoy of medical aid was finally allowed in, minus 50 of its 200 vehicles, after being repeatedly blocked, diverted and intimidated by Egyptian security – including a violent assault in the Egyptian port of El Arish on Tuesday night which left dozens injured, despite the participation of one British and 10 Turkish MPs.

That followed an attempted "Gaza freedom march" by 1,400 protesters from more than 40 countries, only 84 of whom were allowed across the border – which is what led Hedy Epstein, both of whose parents died in Auschwitz, to refuse food in Cairo, as the group's demonstrations were violently broken up and Israel's prime minister Binyamin Netanyahu was feted nearby. Yesterday, demonstrations by Palestinians on the Gazan side of the border against the harassment of the aid convoy led to violent clashes with Egyptian security forces in which an Egyptian soldier was killed and many Palestinians injured.

But although the confrontation has been largely ignored in the west, it has been a major media event in the Middle East which has only damaged Egypt. And while the Egyptian government claims it is simply upholding its national sovereignty, the saga has instead starkly exposed its complicity in the US- and European-backed blockade of Gaza and the collective punishment of its one and a half million people.

The main protagonist of the siege, Israel, controls only three sides of the Strip. Without Egypt, which polices the fourth, it would be ineffective. But, having tolerated the tunnels that have saved Gazans from utter beggary, the Cairo regime is now building a deep underground steel wall – known as the "wall of shame" to many Egyptians – under close US supervision, to make the blockade complete.

That's partly because the ageing Egyptian dictator, Hosni Mubarak, fears cross-border contamination from Gaza's elected Hamas administration, whose ideological allies in the banned Muslim Brotherhood would be likely to win free elections in Egypt.

But two other factors seem to have been decisive in convincing Cairo to bend to American and Israeli pressure and close the vice on Gaza's Palestinians, along with those who support them. The first was a US threat to cut hundreds of millions of dollars of aid unless it cracked down on arms and other smuggling. The second is the need for US acquiescence in the widely expected hereditary succession of Mubarak's ex-banker son, Gamal, to the presidency. So, far from protecting its sovereignty, the Egyptian government has sold it for continued foreign subsidy and despotic dynastic rule, sacrificing any pretence to its historic role of Arab leadership in the process.

From the wider international perspective, it is precisely this western embrace of repressive and unrepresentative regimes such as Egypt's, along with unwavering backing for Israel's occupation and colonisation of Palestinian land, that is at the heart of the crisis in the Middle East and Muslim world.

Decades of oil-hungry backing for despots, from Iran to Oman, Egypt to Saudi Arabia, along with the failure of Arab nationalism to complete the decolonisation of the region, fuelled first the rise of Islamism and then the eruption of al-Qaida-style terror more than a decade ago. But, far from addressing the natural hostility to foreign control of the area and its resources at the centre of the conflict, the disastrous US-led response was to expand the western presence still further, with new and yet more destructive invasions and occupations, in Iraq, Afghanistan and elsewhere. And the Bush administration's brief flirtation with democratisation in client states such as Egypt was quickly abandoned once it became clear who was likely to be elected.

The poisonous logic of this imperial quagmire is now leading inexorably to the spread of war under Barack Obama. Following the failed bomb attack of a Detroit-bound flight on Christmas Day, the US president this week announced two new fronts in the war on terror, faithfully echoed by Gordon Brown: Yemen, where the would-be bomber was allegedly trained; and Somalia, where al-Qaida has also put down roots in the swamp of chronic civil war and social disintegration.

Greater western military intervention in both countries will certainly make the problem worse. In Somalia, it has already done so, after the US-backed Ethiopian invasion of 2006 overthrew the relatively pragmatic Islamic Courts Union and spawned the more extreme, al-Qaida-linked Shabab movement, now in control of large parts of the country. Increased US backing for the unpopular Yemeni government, already facing armed rebellion in the north and the threat of secession from the restive south – which only finally succeeded in forcing out British colonial rule in 1967 – is bound to throw petrol on the flames.

The British prime minister tried this week to claim that the growth of al-Qaida in Yemen and Somalia showed western strategy was "working", because the escalation of the war in Afghanistan and Pakistan had forced it to look for sanctuaries elsewhere. In reality, it is a measure of the grotesque failure of the entire war on terror. Since its launch in October 2001, al-Qaida has spread from the mountains of Afghanistan across the region, to Iraq, Pakistan, the horn of Africa, and far beyond.

Instead of scaling down the western support for dictatorship and occupation that fuels al-Qaida-style terror, and concentrating resources on police action to counter it, the US and its allies have been drawn inexorably into repeating and extending the monstrosities that sparked it in the first place. It's the recipe for a war on terror without end.