We know from the wars in Iraq, Afghanistan and Libya that it is relatively easy for politicians to decide to unleash massive fire on a country and its people — and we know the nightmare that follows, writes John McDonnell, former Shadow Chancellor and Labour MP, in The Independent.

"The hardest part of war is not launching missiles and drones or firing guns, but what happens after the ceasefire, when peace and stability must be ensured."

This is why politicians with such experience are cautious about entering armed conflict without legal certainty that the war is just and compliant with international law, and without a plan not only for the fighting but for a peaceful settlement.

What we are witnessing is the extreme recklessness and irresponsibility of Donald Trump acting in tandem with Benjamin Netanyahu. Trump's attack on Iran was not sanctioned by the UN and is not a response to an immediate and imminent threat. From Trump's own statements, it is clear that the attack aims at regime change — which is entirely contrary to international law and the UN Charter. This is yet another example of Trump undermining the rules-based international order created after World War II to prevent a new global conflict.

It is also clear that Trump has no post-conflict plan — and judging by questions put to Keir Starmer in parliament, the Prime Minister was neither consulted nor informed of any American post-war plan.

The risks are enormous. The war is already spreading to other countries, inflaming the entire region. Britain is not immune: reduced oil supplies are driving up fuel prices, inflation, interest rates and economic stagnation.

Initially Starmer said Britain would not participate. Within hours, however, he performed another U-turn, announcing he would allow the US to use British bases — strictly for defensive purposes — following Iran's missile and drone strikes on neighboring states.

There is some relief that Starmer did not agree to join Trump's attack. But deep concern remains that the legal justification for US use of British bases could later be used to justify further involvement in Trump's war.

A number of MPs, including myself, have demanded that any decision on further British participation be put to a parliamentary vote. We fear that instead of working toward a peaceful resolution, we will be dragged into a catastrophic military adventure by Donald Trump.