The west stood back and watched in Syria – it must not do the same in Ukraine | Hamish de Bretton-Gordon

It's time for the US and its allies to show their steel in the face of Putin's aggression. We have learned that nothing else will work

The Syria crisis continues unnoticed. It holds key lessons for the west about Putin yet it has gone virtually unnoticed by the rest of the world. War crimes and crimes against humanity continue in the Russian-sponsored dictatorship, even as some misguided leaders want to usher Bashar al-Assad, the architect of these crimes, back into acceptable society.

We can rest assured that the president of Ukraine, Volodymyr Zelenskiy, unlike Assad, is not welcoming Putin with open arms. But in responding to the Ukraine emergency, there are lessons the west can and should learn from the situation in Syria.

Hamish de Bretton-Gordon is a chemical weapons expert, fellow of Magdalene College, Cambridge and an adviser to the Union of Syrian Medical Charities