No matter what Boris Johnson or his new Vote Leave cabinet threaten – and the expectation in Brussels is that no-deal planning will be ramped up in an attempt to intimidate other EU countries – be in no doubt: there isn’t time to limit the damage of a sudden severance from the world’s largest trading bloc this Halloween.

Unless a further extension is requested, or article 50 is revoked by 31 October, when the current extension of UK membership expires, a dramatic shock awaits the global economy, and we all stand to lose. The few who may prosper are the wealthy bankers and hedge fund managers who have already bet on chaos.

It is fiction to talk of rewards for citizens or mini-deals to mitigate the damage. Faced with a British government intent on ratcheting up talk of no deal, other European governments have no choice but to prepare for the worst, too – but this is far from a desirable path. In the face of such irresponsible posturing, far from feeling threatened, I fully expect EU governments to remain calm and keep their unity. Attempts to put pressure on Ireland will only be met by waves of solidarity from the rest of the EU.

The European parliament’s Brexit steering group met last week to discuss the new political order in London. We made it clear that Brexit is a British decision and that article 50 can be revoked at any time, as the European court of justice has determined. If an extension is needed, for example for an election, the commission president designate, Ursula von der Leyen, has been clear that this would be considered.

But if Brexit does mean Brexit, we are determined that the negotiated withdrawal agreement, including the backstop, which safeguards the Good Friday agreement, cannot be discarded as Johnson has requested. However, changes are still possible to make the declaration on the future relationship more ambitious, to ensure that the deployment of the Irish backstop is not necessary.

Johnson will find the European parliament an open and constructive partner. I look forward in particular to allaying his concerns regarding the imminent accession of Turkey to the EU, following the claims of the leave campaign he championed, while explaining the EU has no rules on the packaging of kippers in the UK. The EU made a decision to stay out of the UK referendum, but we won’t be afraid to challenge populism and call out disinformation from across the Channel for what it is.

UK-EU relations are at a crossroads. We are re-entering another period of Brexit fever, with the most Eurosceptic cabinet ever formed. Paradoxically, the UK is at the same time calling for a European naval force to protect shipping lanes in the Persian Gulf, as the realities of an America-first foreign policy hit home. No amount of bluster, wishful thinking or fake news can hide the inherent contradictions of the Brexit project.

Despite the irresponsible language of the self-styled disrupters now at the heart of the British government, it is clear that Britain’s prosperity and European security are intertwined. Britain’s rightful place lies at the heart of the European project, fighting for a rules-based liberal world order. Brexit is more than a tragedy – it is a waste of all of our time, in an era when China and the US are fighting for global hegemony and the climate crisis threatens our very existence.

A united Europe could be a bastion of the free world. Together we could become a global leader in tackling the climate emergency and set the terms of global trade. As an anglophile, I still believe the quiet majority of reasonable British people want to see their country engaged as Europeans. The bonds of our collective heritage are too strong for Johnson or Nigel Farage to break. No one should fall into the trap of thinking that a no-deal Brexit is the only way out of the quagmire the Conservative party has led them into.

Johnson repeatedly declares that Britain must leave the EU “do or die” by 31 October, but he misquotes the Charge of the Light Brigade by Alfred, Lord Tennyson:

“Theirs not to make reply / Theirs not to reason why / Theirs but to do and die. / Into the valley of death / Rode the six hundred.”

It is telling that these three words, do or die, misrepresent a poem about a famous British military catastrophe. We must not allow an injurious Brexit strategy, wrongly wrapped up in an English flag, to harm us all.

• Guy Verhofstadt is Brexit coordinator for the European parliament and a former Belgian prime minister