When Boris Johnson settles himself into the big chair in Downing Street he would do well to remember the words of his great hero Winston Churchill - “War is mainly a catalogue of blunders.”

They were words spoken during a different crisis but have lost none of their truth over the decades.

The road to war is similarly plagued and top of the the new Prime Minister’s foreign policy inbox will be the difficult and potentially disastrous situation with Iran.

On one level it’s fairly simple - on another it risks leaving the UK dangerously exposed without strong allies.

The Iranian Supertanker Grace 1 spotted off the coast of Gibraltar. Credit: PA

When the UK seized the Iranian oil tanker the Grace 1 off Gibraltar two weeks ago Iran warned there would be a response and the seizing of the Stena Impero was it.

Now both sides have a large bargaining ship and the next move is down to the UK. There is no way Iran will back down as long as the UK has one of its ships.

However the problem for Boris Johnson, is not just his troubled relationship with Iran, it’s his troubled and needy relationships with everyone else.

The official reason given for seizing the Grace 1 was that she was carrying oil to Syria and breaking EU sanctions. Releasing her would destroy any semblance of respect for European law.

Iran believes the British seized their ship on the orders of the United States as part of the US’s efforts to force them to negotiations over their nuclear arsenal. If that’s the case then releasing it risks compromising the relationship between Number 10 and the White House before it really gets going. That in turn compromises any post-Brexit free trade deal.

There is little appetite for negotiation on either side but equally there is little real appetite for conflict. The danger is that too many blunders could lead us all there.