I don’t like Starmer very much, but that’s a utterly stupid and incredibly ignorant thing to say. Especially from the US ambassador.

The UK was under attack by a hostile force who were literally bombing the country. A military response was inevitable, the current prime minister would have had very little effect on that. One way or the other there was going to be a war, victory for that war was largely down to experience military commanders and not the prime minister. I’m fairly sure that if we reran history and kept everything else the same except had Starmer as prime minister we would have still won the war.

In reality we might have done slightly better because Churchill was incredibly uncompromising and inflexible. A better relationship with Eisenhower might have actually helped slightly. Although it probably would have not made a huge difference.