We may have known the outline of the global US kidnapping and torture programme for a few years. But even the heavily censored summary of the US senate torture report turns the stomach in its litany of criminal barbarity unleashed by the CIA on real and imagined US enemies.

The earlier accounts of US brutality in Abu Ghraib and Guantánamo pale next to the still sanitised record of forced rectal “infusions” and prolapses, multiple “waterboarding” drownings and convulsions, the shackled freezing to death of a man seized in a mistaken identity case, hooded beatings and hanging by the wrists, mock executions, and sleep deprivation for up to 180 hours.

What has been published is in fact only a small part of a much bigger picture, including an estimated 100 or more prisoners tortured to death in US detention. Added to the rampant lying, cover-ups and impunity, it’s a story that the champions of America’s “exceptionalism” will find hard to sell around the world. And it’s hardly out of line with a CIA record of coups, death squads, torture schools and covert war stretching back decades, some revealed by an earlier senate report in the 1970s.

There is of course nothing exceptional about states that preach human rights and democracy, but practise the opposite when it suits them. For all the senate’s helpful redactions, Britain has been up to its neck in the CIA’s savagery, colluding in kidnapping and torture from Bagram to Guantánamo while dishing out abuses of its own in Iraq and Afghanistan.

So you’d hardly think this reminder of the horrors unleashed in the name of the war on terror was the time for Britain to announce its first permanent military base in the Middle East for four decades. The presence of western troops and support for dictatorial Arab regimes were, after all, the original reasons given by al-Qaida for its jihad against the west.

The subsequent invasions, occupations and bombing campaigns led by the US, Britain and others have been endlessly cited by those who resisted them in the Arab and Muslim world, or launched terror attacks in the west. But last week, foreign secretary Phillip Hammond proudly declared that Britain would reverse its withdrawal from “east of Suez” of the late 1960s and open a navy base “for the long term” in the Gulf autocracy of Bahrain.

The official talk is about protecting Britain’s “enduring interests” and the stability of the region. But to those fighting for the right to run their own country, the message could not be clearer. Britain, the former colonial power, and the US, whose 5th Fleet is already based in Bahrain, stand behind the island’s unelected rulers. No wonder there have already been protests against the base.

Bahrainis campaigning for democracy and civil rights, in a state where the majority are Shia and the rulers Sunni, were part of the Arab uprisings in 2011. With US and British support, Saudi Arabia and the UAE crushed the protests by force. Mass arrests, repression and torture followed.

Three years later, Bahrain’s human rights situation has got worse, and even the US government voices concerns. But British ministers purr about the “progress” of the monarchy’s “reforms”, praising phoney elections to a toothless parliament, boycotted by the main opposition parties. Last week Bahraini activist Zainab al-Khawaja was sentenced to three years in jail for tearing up the king’s photograph. Her father, Abdulhadi, is already serving a life sentence for encouraging peaceful protest.

In reality, the British base’s main job won’t be to prop up the Bahraini regime, but to help protect the entire network of dictatorial Gulf governments that sit on top of its vast reserves of oil and gas – and provide a springboard for future interventions across the wider Middle East. British troops never really left the region and have been part of one intervention after another.

The US itself controls an archipelago of military bases across the Gulf: in Kuwait, Qatar, Oman and the UAE, as well as Bahrain. And despite Barack Obama’s much-heralded pivot to Asia, they are also clearly there for the long haul. After the US accepted the overthrow of the Egyptian dictator Mubarak three years ago, the Gulf autocrats are looking for extra security, which Britain and France are glad to provide. For the London elite, the Gulf is now as much about arms sales and finance as about oil and gas – and a web of political, commercial and intelligence links that go to the heart of the British establishment.

So the British military is also looking to beef up its presence in the UAE, Oman, Qatar and Kuwait. The crucial thing is that these colonial creations remain in the grip of their ruling families and democratisation is put on the back burner. That’s the only guarantee that this corrosive relationship will endure – on the back of disenfranchised populations and armies of grotesquely exploited migrant labour.

On a larger scale, the return of western-backed dictatorship in Egypt, the Arab world’s most important country, has helped re-establish the conditions that led to the war on terror in the first place. Obama has traded the CIA’s Bush-era kidnap-and-torture programme for expanded special forces and CIA drone killings, often of people targeted only by their “signatures” – such as being males of military age. And British forces have this week been accused of training and providing intelligence for Kenyan death squads targeting suspected Islamist activists.

The impact of all this – the revelations of the CIA’s torture orgy, the growing western military grip, the vanishing chances of democratic change – on the Arab and Muslim world should by now be obvious, along with the social backlash in countries such as Britain.

But with its new commitment to station troops in Bahrain, we can have no doubt where the British government stands: behind autocracy and “enduring interests”. Just as the refusal to hold previous US governments to account for terror and torture laid the ground for what happened after 9/11, the failure of parliament even to debate the decision to garrison the Gulf is an ominous one. Britain’s new base isn’t in the interests of either the people of Britain, Bahrain or the Middle East as a whole – it’s a danger and affront to us all.