A CLARION call will ring through Bloomsbury’s Central Baptist Church today. Its echoes will carry a message of peace and hope — and a warning to the left.

Stalwarts of our anti-war movement such as Tariq Ali and Lindsey German will gather with US activists like Codepink’s Medea Benjamin and pioneers of the left’s new media, in a counter-summit to the Nato meeting being held in London next week.

This clarion call will remind us how much there is left to do if we are to truly change Britain and the world.  

After all, not only will London play host to the Nato leaders’ meeting next week, but Buckingham Palace will host President Donald Trump for a banquet celebrating 70 years of the destructive Atlantic alliance.

Trump’s visit reminds us of the stark choice at this election, between socialism or barbarism, internationalism or Atlanticism.  

Labour’s manifesto is clear in its objectives — a Labour government would end the outsourcing of British foreign policy to Trump, introduce a war-powers Act ensuring Parliament has the final say on any troop commitments, conduct an impact audit of Britain’s ruthlessly violent colonial legacy and invest £400 million in our diplomatic capacity so that we can be a vessel for peace, not a vassal for the US war industry.

The movement we are building inside and around the Labour Party since Jeremy Corbyn was elected as our leader is only just beginning to take shape.  

It is our responsibility to ensure that Labour wins this election and is then able to carry out its manifesto pledges.  

We are a people-powered movement and the time may come to unleash that people power.  

If our domestic and foreign-policy objectives are thwarted in government by the same forces now arrayed against the prospect of a Corbyn premiership, we must be ready to take to the streets.

Jeremy has been clear from the outset that he needs our support so he can hold the line.  

The youthful naivety in this new movement has meant that the profundity of those words has not always been understood.  

In power, it is sometimes difficult to introduce new and necessary ideas without meeting resistance from cautious technocrats or advisers who think in terms of 24-hour news cycles rather than 30-year culture shifts.  

Supporting this leader means being canny enough to recognise when he is being forced into a position against his better judgement.  

It means saying the things he cannot say and going further than he does to make space for him to represent our will.

Instead, our movement has at times fallen in line behind the conservative approach foisted upon Jeremy – often by colleagues who are not actually supporters of a socialist transformation of Britain.  

Nowhere have the effects of this approach been clearer than in the movement’s timidity in failing to dismiss manufactured charges of anti-semitism.  

The consistent indulgence of this — accepting a massively distorted picture of the state of the Labour Party painted by our enemies — only emboldens the racists that have executed this smear campaign to go ever further in rewriting history.  

We cannot allow the same embarrassing spectacle to derail our clear-eyed position on the dangers of Atlanticism.

Make no mistake, there will be another force in our way. The shape and structure of the US lobby in Westminster is completely different from that of Israel’s partisans.

Whereas much of the Israel apologism is overt, the US lobby is discreet and opaque.  

In methods and structure, it is far more akin to the lobbies of the United Arab Emirates and Saudi Arabia.  

It operates largely in private, influencing and instrumentalising military top brass, former and current intelligence officials and defence think tanks. 

In Parliament, it works through lobby groups like the Henry Jackson Society and the British-American Project.  

It exists to launder the consequences of US power, influence MPs and maintain Britain’s role as an accessory to US war crimes.

There is a thirst to take back control of our destiny among the voters left behind by the destruction wrought by four decades of the transatlantic neoliberal consensus.  

We on the left must be clearer about the causes of this economic and social catastrophe.  

The European Union is an important barrier to a socialist future here in Britain. 

But it is the US war industry that has eroded our sovereignty and public trust in the potential of politics far more than Brussels bureaucrats.

The Trident nuclear weapons system, that Jo Swinson is so keen to protect, is effectively a US boondoggle merely managed by the Royal Navy until such time as the US demands we use it.  

The missiles are American, and we would be naive to assume that Nato’s Allied Maritime Command at Northwood headquarters would not determine when those missiles would be fired, leading to potential genocide and certain environmental disaster.

If we’re taking back control, we must start by recovering our sovereignty from the state that poisons our politics, suffocates our culture and occupies our territory.  

Today, that message will be heard just minutes from where the faux-left Euston Manifesto — designed to stifle anti-imperialism on the left — was conceived in 2006.  

The left belongs to us again. We must now secure a Labour government to ensure that our vision of a hopeful, prosperous and peace-making Britain becomes a reality so that the future belongs to all our people.