The Brexit poison in the British polity has also infected Europe.

Britain is finished with Europe. Equally, Europe is finished with Britain.

The angry British sentiment to get the thing done is matched by an exasperated European response: Be gone!

My previous column on the Brexit lunacy offered three conclusions that can be stated as established facts about Britain’s future: it will be politically polarised, economically poorer and have less diplomatic and strategic power.

Britain’s relationship with Europe is deeply damaged. Europe sees Britain as dangerous and a bit deranged. Europe isn’t going to bother any more. It’s over—for both sides.

The poisoned European view is one of the many flaws in Prime Minister Boris Johnson’s tactic of forcing a better ‘deal’ out of the EU by driving full speed towards a no-deal cliff.

To put this into wide focus, ponder the question: What is Britain’s future grand strategy?

Since World War II, Britain’s strategy could be grouped under the headings of ‘global player’, ‘Europe’ and ‘the US’.

The global dimension covered Britain’s values and interests as an international trading and financial centre, plus major multilateral responsibilities, especially as a permanent member of the UN Security Council and Commonwealth leader.

The chance to play a bigger global game when free of those ghastly Europeans is core Brexit propaganda, yet it sits uncomfortably beside the ‘Little England’, nativist frothing. Britain is raising serious questions about the values and interests it will be able to represent on the international stage.

In Europe, Britain’s traditional strategy as the offshore balancer was enhanced by its membership of the great European project and NATO. Britain is still in NATO, but the poison means its views on military policy will be challenged. The rest of Europe isn’t going to listen to a nation dismissed as dangerous and deranged.

The same tough calculus applies to the special relationship with the US. The global and European roles were important elements of what Britain brought to Washington. A Britain that speaks only for itself speaks with a weaker voice.

How has it come to this?

Brexit has been a slow-motion disaster that’s accelerating as it reaches its climax, offering many lessons about what poisoned politics do to a country.

Leaders should be careful about asking their people dumb questions, because there’s a big risk of getting a dumb answer back. The Brexit referendum was a simple yes/no call on complex questions. It was a yes/no judgement on British grand strategy. It was simply silly to force such complexity into a binary question.

Leaders are paid to lead, not to evade tough calls to appease their party. In the court where history will judge, David Cameron stands accused.

The former prime minister is the man guilty of asking Britain a profoundly complex question, while knowing the question should never have been posed. The Brexit question dealt in absolutes when democratic politics (and grand strategy) is always a matter of degrees.

Johnson may yet grab the title, but for now Cameron has taken over from Neville Chamberlain as the worst prime minister in 100 years.

Chamberlain grossly misjudged Hitler, but he was striving to avoid a repeat of the cataclysm of 1914–18. Chamberlain failed, but he was doing proper duty in striving to avoid a second world war.

No such judgement of high aim and duty applies to Cameron. The ‘peace in our time’ Cameron sought was merely for the Conservative Party. To hold the Tories together and hold power, Cameron gambled Britain’s economic and strategic future. He risked not just ties with Europe, but the unity of the nation.

Having won a referendum to keep Scotland in the United Kingdom, Cameron then called on a vote that has created a disunited kingdom. Scotland turns its eyes away from the UK towards Europe. Northern Ireland again faces tough choices about its place in the UK and family ties with Ireland.

Leaders can tear their nations apart merely for a bit of peace in the party (Cameron), or to serve their towering ego (Johnson), or by incompetence, as Theresa May demonstrated. May was dealt a dreadful hand and played it badly.

To those thoughts about government and leadership, add the stark point that political parties can suffer from neuroses, obsessions and nervous breakdowns.

The Tories and the Labour Party are each guilty of turning inwards to fight their own demons. As they’ve consumed themselves, Labour has veered left while the Tories have gone sharp right to become the Leave party.

The parties of government have deserted the middle ground. Britain has had dismal service from its political class.

Chaos suits Johnson. Perhaps he’s the man for the times. His greatest fortune is his opponent, Labour leader Jeremy Corbyn.

At the election which will soon come, Britain will choose between the zany and zealot. The fanatic will face the fanciful.

Zany Johnson will campaign as the safe choice compared with the Labour zealot. Remember, though, that May raged about the socialist devil at the previous election and nearly handed victory to Corbyn.

Johnson is a mercurial chancer with an ambition more uncontrolled than his hair. The questions to be answered in coming weeks are whether his understanding of power matches his will to power, whether his glibness can stretch to vision, and whether he’s as smart as he is sharp.

On-the-job training is fine, but these aren’t the fundamental puzzles you want to contemplate when gazing at your new prime minister.

My closing line was going to be that Johnson is a chameleon crossing a kilt—but that doesn’t work because Scotland will kick Boris black and blue in the election.

Instead, see Boris as a chameleon crossing the red, white and blue of the Union Jack. The product of Oxford and Eton campaigns as a true-blue tribune of the people, fighting the elites until he’s red in the face. And as he careers across the country, many go white with fear.